Dell VMware VSAN Ready Nodes vLab Guide - Amazon S3...Dell | Global Sales Learning & Development...
Transcript of Dell VMware VSAN Ready Nodes vLab Guide - Amazon S3...Dell | Global Sales Learning & Development...
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Dell VMware VSAN Ready Nodes vLab Guide
Converged Infrastructure
Dell confidential
Dell
Document version 1.0
Date: May 2016
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Table of Contents
Demonstration Labs ........................................................................................................................... 4
Introduction ....................................................................................................................................... 4
Preparing the Demo Environment ................................................................................................ 5
Module 1 - All Flash VSAN 6.2 Cluster (30 Minutes) ........................................................................ 6
All Flash VSAN Cluster........................................................................................................................... 6
View Available Storage Devices ...................................................................................................... 8
Enable Virtual SAN on the cluster ................................................................................................... 9
Turn on Virtual SAN ......................................................................................................................... 10
Verify Network validation ............................................................................................................... 11
Enable the VMkernel VSAN traffic service ................................................................................... 12
Enable Virtual SAN on the cluster ................................................................................................. 14
Turn On Virtual SAN ........................................................................................................................ 15
Verify Network validation ............................................................................................................... 17
Ready to Complete ......................................................................................................................... 20
Verify VSAN Health .......................................................................................................................... 24
Module 1 - Conclusion ................................................................................................................... 33
Module 2 - Enabling Performance Service (30 Minutes) ......................................................... 34
Enabling Performance Service .......................................................................................................... 34
Monitor Virtual SAN Performance - Cluster ............................................................................... 39
Module 2 - Conclusion .................................................................................................................. 41
Module 3 - Storage Based Policy Management (30 Minutes)................................................. 42
Storage Based Policy Management ................................................................................................. 42
Raid 5/6 (Erasure coding) ............................................................................................................... 45
Disk Policies - FTT=1 Raid 5 .......................................................................................................... 56
Implement Raid 6 - Disk Policies .................................................................................................. 59
Module 4 - Sparse VM Swap Object (30 Minutes) ..................................................................... 62
New Sparse VM Swap Object ............................................................................................................ 62
New Sparse VM Swap Object ........................................................................................................ 63
Module 4 - Conclusion .................................................................................................................. 64
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Module 5 - Virtual SAN Stretched Cluster (ROBO) (30 Minutes) ........................................... 65
Virtual SAN Stretched Cluster (ROBO) ............................................................................................. 65
Configure Virtual SAN Stretched Cluster .................................................................................... 66
vSphere HA and DRS settings for VSAN Stretched Cluster ...................................................... 84
VM/Host Groups .............................................................................................................................. 85
Enabling HA in VSAN Stretched Cluster ...................................................................................... 90
Module 5 - Conclusion ...................................................................................................................... 105
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Demonstration Labs
Introduction
This lab covers the new features in Virtual SAN 6.2
There are 5 modules in the training:
1. All Flash VSAN Cluster : Virtual SAN clusters contain two or more physical hosts that
contain either a combination of magnetic disks and flash devices ( hybrid configuration ) or
all flash devices ( all-flash configuration ) that contribute cache and capacity to the Virtual
SAN distributed datastore. Virtual SAN uses deduplication and compression to eliminate
duplicate data. These techniques reduce the total storage required to meet your needs.
2. Enabling Performance Service: When you create a new Virtual SAN cluster, the
performance service is disabled. Turn on Virtual SAN performance service to monitor the
performance of Virtual SAN clusters, hosts, disks, and VMs. When you turn on the
performance service, Virtual SAN places a Stats database object in the datastore to collect
statistical data. The Stats database is a namespace object that resides in the cluster's Virtual
SAN datastore. In this task you will enable the performance service.
3. Storage Based Policy Management: Virtual SAN 6.2 introduces space efficiency
technologies optimized for all-flash configurations to minimize storage capacity
consumption while ensuring performance and availability. These new features include
RAID5/6 erasure coding to reduce capacity consumption while ensuring the same levels of
availability and performance for a lower total cost of ownership. Another SPBM feature is
Object Checksum. This will ensure that you have data integrity in your VSAN Cluster.
Checksum is available on both hybrid and all-flash configurations of VSAN.
4. Sparse VM Swap Object: This new feature can provide a considerable space-saving on
capacity space consumed by deploying VM swap as thin. This will rely on how many VMs you
have deployed, and how large the VM swap space is (essentially the size of unreserved
memory assigned to the VM).
5. Virtual SAN Stretched Cluster : Features such as Fault Domains, 2-node VSAN and VSAN
stretched cluster now have new wizards to make the whole setup process very straight-
forward. The goal of keeping VSAN “radically simple” is still at the heart of VSAN
development.
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Preparing the Demo Environment
Activation Prompt or Watermark
When you first start your lab, you may notice a watermark on the desktop indicating that
Windows is not activated.
One of the major benefits of virtualization is that virtual machines can be moved and run on
any platform. The Hands-on Labs utilizes this benefit and we are able to run the labs out of
multiple datacenters. However, these datacenters may not have identical processors, which
triggers a Microsoft activation check through the Internet.
Rest assured, Dell and demos.dell.com are in full compliance with Microsoft licensing
requirements. The lab that you are using is a self-contained pod and does not have full
access to the Internet, which is required for Windows to verify the activation. Without full
access to the Internet, this automated process fails and you see this watermark.
This cosmetic issue has no effect on your lab. If you have any questions or concerns, please
feel free to contact us.
A note on the keyboard
Note : If you are not using a US keyboard be aware that the “ and @ symbols may be reversed
or in different locations, depending on how you connect.
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You can click on the Keyboard icon on the System Tray of the ControlCenter VM to pop up an
onscreen keyboard.
Module 1 - All Flash VSAN 6.2 Cluster (30 Minutes)
All Flash VSAN Cluster
Virtual SAN can be configured with all-flash or hybrid storage. Typically in earlier versions of
VSAN there is just one flash disk (SSD) per disk group, for read and write caching. All the other
disks in the disk group are used for capacity, and are regular magnetic SAS or SATA hard
disks. This is known as hybrid VSAN configuration.
Creating an All Flash Virtual SAN means that flash disks (SSDs ) can be used for both caching
and for capacity tiers.
An All Flash VSAN datastore can be configured using just the vSphere Web Client.
Log in to vSphere Web Client
To start the vSphere Web Client, launch Mozilla Firefox from the icon on your desktop.
Log in to the vSphere Web Client using the following credentials or tick the Use Windows
session authentication
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User name : [email protected] Password : VMware1!
Click Login
Navigate to Hosts and Clusters
From the Home page in the vSphere Web Client, select Hosts and Clusters from the
Inventories pane
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View Available Storage Devices
1. Select the ESXi host called esx-01a.corp.local from the Hosts and Clusters view.
2. Select Manage
3. Select Storage
4. Select Storage Devices
The Disks highlighted above are Flash Disks. There are 2 disks of 5 GB in size and will be used
for caching tier, the other 4 are 10 GB in size and will be used for capacity tier.
These are the Disks that we will use to form the VSAN Cluster.
Check the other three hosts (esx-02a.corp.local, esx-03a.corp.local, esx-04a.corp.local)
and confirm that they too have 2 X 5 GB and 4 X 10 GB Flash disks.
It is now time to form our VSAN Cluster.
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Enable Virtual SAN on the cluster
1. Select the cluster called Cluster Site A
2. Select Manage
3. Select Settings
4. Select Virtual SAN
5. Select General
6. Click the Configure... button
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Turn on Virtual SAN
Here we will introduce the new Configure Virtual SAN wizard.
From here you can decide if you want to select Manual or Automatic disk claiming, if you
want to enable Deduplication and Compression when creating the Disk Groups and options
for Fault Domains and Stretched Cluster.
In our environment, we already have a VSAN Cluster created, but we will turn it on. We will
also look at the additional checks that we have incorporated into the Virtual SAN
configuration wizard.
Verify Add disks to storage is set to Manual
Verify Deduplication and Compression is Enabled
Verify Fault Domains and Stretched Cluster is set to Do Not configure
To get a quick overview of these features, click the information (i) next to the feature.
Click Next
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Verify Network validation
Checks have been put in to verify that there are VMkernel adapters configured and the VSAN
network service is Enabled.
Notice that the ESXi host called esx-04a.corp.local is reporting that there are no VMkernel
adapters with VSAN traffic enabled.
Let's fix this by enabling the VSAN traffic on these VMkernel adapters.
Click Cancel
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Enable the VMkernel VSAN traffic service
1. Select the ESXi host called esx-04a.corp.local from the Hosts and Clusters view.
2. Select Manage
3. Select Networking
4. Select VMkernel adapters
Here you will see that we have 2 VMkernel adapters called VSAN-PG-vmk3 and VSAN-PG-
vmk4. These are the 2 VMkernel adapters on which we will enable the VSAN traffic Service.
Select VSAN-PG-vmk3 and click the Pencil icon to Edit the VMkernel adapter.
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Enable the VMkernel VSAN traffic service
In the Port Properties, select the Virtual SAN traffic option.
Click OK
Enable the VMkernel VSAN traffic service
Edit the Properties of the VSAN-PG-vmk4 and enable the Virtual SAN traffic.
Click OK
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Enable the VMkernel VSAN traffic service
Once we have enabled the Virtual SAN traffic on the VMkernel ports, verify that the Virtual
SAN traffic is enabled.
Here we are showing the 2 VMkernel Ports and the Virtual SAN traffic is enabled.
You may have to scroll to the right of the screen to see the Virtual SAN traffic column.
Now that we have completed this task, let’s create our Virtual SAN Cluster.
Enable Virtual SAN on the cluster
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1. Select the cluster called Cluster Site A
2. Select Manage
3. Select Settings
4. Select General
5. Click the Configure... button
Turn On Virtual SAN
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In our environment, we already have a VSAN Cluster created, but we will turn it on. We will
also look at the additional checks that we have incorporated into the Virtual SAN
configuration wizard.
Verify Add disks to storage is set to Manual
Verify Deduplication and Compression is Enabled
Verify Fault Domains and Stretched Cluster is set to Do Not configure
To get a quick overview of these features, click the information (i) next to the feature.
Click Next
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Verify Network validation
Checks have been put in to verify that there are VMkernel adapters configured and the VSAN
network service is Enabled.
Notice that the ESXi host called esx-04a.corp.local is now reporting that there are VMkernel
adapters with VSAN traffic enabled.
Click Next
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Claim Disks by Disk model/size
As we called out earlier, we are turning on VSAN. We already have a VSAN cluster created,
but here we are adding additional Disk Groups to the VSAN Cluster.
Select which disks should be claimed for cache and which for capacity in the VSAN cluster.
The disks are grouped by model and size or by host.
The recommended selection has been made based on the available devices in your
environment. You can expand the lists of the disks for individual disk selection.
The number of capacity disks must be greater than or equal to the number of cache disks
claimed per host.
From the Group by drop down list, select Host
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Claim Disks by Host
In the Group by : Host view, we can see that all the disks are already claimed in the ESXi
hosts called esx-01a.corp.local, esx-02a.corp.local and esx-03a.corp.local.
For ESXi host called esx-04a.corp.local, we can see that there will be 2 Disk Groups created,
that is one Flash disk and 2 Capacity disks in each Disk Group.
Click Next
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Ready to Complete
Review and verify your selection.
Here we can see that Deduplication and Compression are Enabled.
We will have a Total VSAN capacity of 160 GB, 120 GB of this is already claimed in Disk
Groups, the remaining 40 GB will be created when we create the additional Disk Group on
the ESXi host called esx-04a.corp.local
We are not configuring Fault Domains and Stretched Cluster
Click Finish
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Wait for cluster reconfiguration to complete
You can monitor the tasks by clicking on the My Tasks at the bottom left of the vSphere Web
Client.
Wait for the Reconfigure Virtual SAN configuration tasks to complete.
Verify initial VSAN cluster configuration
Once the VSAN datastore is created, the General screen will be updated.
We can see that Virtual SAN is now Turned On. Deduplication and compression is Enabled
and all disks in the Disk Groups are at Disk format version 3.0.
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Examine new Disk Groups
1. Select the cluster called Cluster Site A
2. Select Manage
3. Select Settings
4. Select Disk Management
The Virtual SAN Disk Group(s) will be created on each individual ESXi Host.
Selecting an ESXi Host or Disk Group will show the disks it contains and the role each disk
plays (cache or capacity).
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Examine new Disk
You can change to the disks view by clicking on the Disks link on the top right of this screen
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Verify VSAN Health
A number of VSAN Health alarms are triggered during the VSAN cluster configuration
process.
These can be ignored, and/or acknowledged and reset to green. They do not affect the rest
of the lab.
For the Hardware compatibility test, these will always show as a Warning as we are running
in a virtualized environment.
If you see Network Partition failures, wait for a moment and run the tests again.
Click the Retest button to run the VSAN Health Check again.
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Verify VSAN Health
Expand the Hardware Compatibility.
Here you can see that we have checked the Hardware ( Controller Driver, Controller
Release, and SCSI Controller ) from the VMware Hardware Compatibility List.
In our Lab environment, these will always show as a warning as we are running in a
virtualized environment.
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Verify VSAN Health
Expand the Performance service.
The Performance service is showing as a warning because we have not enabled it yet. We
will do this in a later task.
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Virtual SAN HCL Database
Select the Cluster Cluster Site A -> Manage -> Settings -> Health and Performance
The Virtual SAN HCL DB can be kept up to date from the Health and Performance screen.
You can upload an updated HCL db from a file or you can update from the online version.
Note: You may not have an Internet connection from your lab environment, so you will not
be able to update the HCL Database.
Examine the new VSAN datastore
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1. Switch to the Datastores view.
2. Select the new VSAN datastore (vsanDatastore)
3. Review the basic details in the Summary tab.
We have now successfully created an All Flash VSAN Cluster.
Get VSAN information from the command line (esxcli vsan)
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Open the PuTTY icon on your desktop.
Select the session called esx-01a.corp.local , you will be automatically logged in to the ESXi
Host.
For reference, the root password is VMware1!
Get VSAN Cluster information
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The vSphere CLI command set allows you to run common system administration commands
against vSphere systems from an administration server of your choice.
'esxcli vsan' is the namespace for VSAN management commands.
To get help, run 'esxcli vsan --help'
[root@esx-01a:~] esxcli vsan Usage: esxcli vsan {cmd} [cmd options] Available Namespaces: cluster Commands for VSAN host cluster configuration datastore Commands for VSAN datastore configuration network Commands for VSAN host network configuration storage Commands for VSAN physical storage configuration faultdomain Commands for VSAN fault domain configuration maintenancemode Commands for VSAN maintenance mode operation policy Commands for VSAN storage policy configuration trace Commands for VSAN trace configuration
To get information on the Virtual SAN Cluster that this host is joined to, run the following
command:
esxcli vsan cluster get
The command esxcli vsan cluster get, when run on individual ESXi hosts, can tell if a host is
participating in the Virtual SAN cluster.
Running the command on an ESXi host that is part of a healthy 4-node VSAN cluster is
shown above.
The local node UUID can be retrieved from the output. You can also see the Sub-Cluster
Member UUIDS, of which there are four.
Get VSAN Network information
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To participate in a Virtual SAN cluster, and form a single partition of fully connected ESXi
hosts, each ESXi host in a VSAN cluster must have a vmknic (VMkernel NIC or VMkernel
adapter) configured for Virtual SAN traffic.
Note: Even if an ESXi host is part of the Virtual SAN cluster, but is not contributing storage, it
must still have a VMkernel NIC configured for Virtual SAN traffic.
Query VSAN network configuration at the ESXi host level:
esxcli vsan network list
In our output, the VMkernel nic vmk3 and vmk4 are used for Virtual SAN traffic.
We can also see the Multicast configuration from this output.
Get VSAN Storage information
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Query local disk information in the ESXi host:
esxcli vsan storage list
We can use esxcli vsan storage list to check if the Disk is an SSD disk, if the disks are claimed
by CMMDS ( Cluster Monitoring, Membership, and Directory Service). We can also see the
On-disk format version.
We can also check whether Deduplication and Compression are enabled.
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Finally, whether the disk is participating in the Cache or Capacity tier in the VSAN diskgroup.
Get VSAN Policy information
Query the default policy in the VSAN cluster:
esxcli vsan policy getdefault
By default, an N+1 failures to tolerate policy is applied so that even in the case where user
forgets to create and set a policy objects are made resilient. It is not recommended to
change the default policy.
Module 1 - Conclusion
In this module we walked through the steps to enable an all-flash VSAN Cluster. We
demonstrated the new Virtual SAN configuration wizard and the additional VSAN traffic
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VMkernel checks. We added an additional Disk group to the VSAN cluster to increase the
capacity of the vsanDatastore. We took our first look at the VSAN Health Check. Finally we
looked at some of the command line ( esxcli ) tools to query information about the VSAN
cluster configuration.
Module 2 - Enabling Performance Service (30 Minutes)
Enabling Performance Service
When you create a new Virtual SAN cluster, the performance service is disabled. Turn on
Virtual SAN performance service to monitor the performance of Virtual SAN clusters, hosts,
disks, and VMs.
When you turn on the performance service, Virtual SAN places a Stats database object in the
datastore to collect statistical data. The Stats database is a namespace object that resides in
the cluster's Virtual SAN datastore.
Before you enable the Virtual SAN performance service, make sure the cluster is properly
configured and has no outstanding health issues.
With the release of the Virtual SAN 6.2 Performance Service, VMware is providing basic
Virtual SAN performance reporting from the vSphere Web Client. The goals are to have this
feature “always on”, fully integrated with the vSphere Web Client UI, easy to access and
consume, and maintain historic data of VSAN performance.
A Virtual SAN namespace object is used to store a statistics database (stats DB). The object is
a regular object (stats object), and has a policy associated with it. The policy is chosen when
the administrator enables the performance service. If no specific policy is chosen, the default
VSAN datastore policy is used. The default policy has NumberOfFailuresToTolerate set to 1,
which implies that if there is a failure in the VSAN cluster, the performance service is not
impacted and will continue to run. Therefore the performance service has no single point of
failure.
On each ESXi host in the VSAN cluster, the performance service runs a daemon to collect
performance metrics. The metrics are calculated as an average over 5 minute intervals. The
stats collection is always on. These statistics are stored in the stats DB in the stats object. This
implies that the vCenter server is not required for any aspect of the stats infrastructure, such
as setup, collection, storage, and query.
Enabling Performance Service
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When you create a new Virtual SAN cluster, the performance service is disabled.
To enable the performance service, VSAN must be configured on the cluster.
Select the Cluster called Cluster Site A
Select Manage
Select Settings
Select Health and Performance
Click Edit
Enabling Performance Service
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Select the Turn On Virtual SAN performance service check box.
Select a storage policy for the Stats database object.
Select the Virtual SAN Default Policy
The Virtual SAN Default Storage Policy is selected by default. This includes the policy
attribute of NumberOfFailuresToTolerate set to 1, making the performance service highly
available.
Click OK
Enabling Performance Service
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Check the Recent Tasks pane.
The Enable Virtual SAN performance service task will be executed.
Enabling Performance Service
Select Cluster Site A -> Manage -> Settings -> Health and Performance
On examining the status of the performance service after it has been enabled, a status similar
to the following should now be seen.
From here you can also Turn off or Edit the Storage policy in use by the Performance
service.
Enabling Performance Service
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Select Cluster Site A -> Monitor -> Virtual SAN -> Health
Click the Retest button to rerun the VSAN Health Check
Here we can see that the Performance service Health Checks have now passed, once we
have enabled the Performance service.
Expand the Performance service and select the individual Performance service checks for
more information.
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Monitor Virtual SAN Performance - Cluster
Select Cluster Site A -> Monitor -> Performance -> Virtual SAN - Virtual Machine
Consumption
You can use Virtual SAN performance service to monitor the performance of your Virtual
SAN environment, and investigate potential problems.
The performance service collects and analyzes performance statistics and displays the data in
a graphical format so that you can determine the root cause of problems. You can view
performance charts for the cluster, and for each host, disk group, and disk in the Virtual SAN
cluster. You also can view performance charts for virtual machines and virtual disks.
The Virtual SAN Performance Service displays performance charts that you can use to
monitor the workload and help you determine the root cause of problems.
When the Performance Service is turned on, the cluster Summary displays an overview of
Virtual SAN performance statistics, including Virtual SAN capacity, throughput, IOPS, and
latency. At the cluster level, you can view detailed statistical charts for virtual machine
consumption and the Virtual SAN back-end.
We have no Performance data to graph yet, but we can return to these Performance
Graphs in later modules.
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Monitor Virtual SAN Performance - Cluster
Select Cluster Site A -> Monitor -> Performance -> Virtual SAN - Backend
Virtual SAN displays performance charts for the host back-end operations, including IOPS,
throughput, latency, congestion's, and outstanding IOs.
We do not have any data to show yet. On each ESXi host in the VSAN cluster, the
performance service runs a daemon to collect performance metrics.
The metrics are calculated as an average over 5 minute intervals.
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Monitor Virtual SAN Performance - Hosts
There are similar Performance Graphs available at a Host level.
Select esx-01a.corp.local > Monitor -> Performance
The graphs available here are :
Virtual SAN - Virtual Machine Consumption
Virtual SAN - Backend
Virtual SAN - Disk Group
Virtual SAN – Disk
Module 2 - Conclusion
In this module we showed how to enable the VSAN Performance service which is disabled by
default. The new VSAN performance service will have its own separate database on the VSAN
datastore and can be protected with a VM Storage Policy. All the graphs for the performance
service can be found under the Performance > Monitor view when a cluster, host or VM is
selected in the vCenter server inventory. It's now easy to monitor Virtual SAN from within the
vSphere Web Client.
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Module 3 - Storage Based Policy Management (30 Minutes)
Storage Based Policy Management
When you use Virtual SAN, you can define virtual machine storage requirements, such as performance
and availability, in the form of a policy. Virtual SAN ensures that the virtual machines deployed to
Virtual SAN datastores are assigned at least one virtual machine storage policy.
Once assigned, the storage policy requirements are then pushed down to the Virtual SAN layer when a
virtual machine is being created. The virtual device is distributed across the Virtual SAN datastore to
meet the performance and availability requirements.
When you know the storage requirements of your virtual machines, you can create a storage policy
referencing capabilities that the datastore advertises.
You can create several policies to capture different types or classes of requirements.
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Storage based Policy Management
Virtual SAN 6.2 adds a number of new Storage Policies, namely Disable object checksum,
Failure tolerance method and IOPs limit for object.
We are giving a brief description of each of the Storage Policies here.
Number of disk stripes per object - The number of capacity devices across which each
replica of a virtual machine object is striped. A value higher than 1 might result in better
performance, but also results in higher use of system resources.
Flash read cache reservation - Flash capacity reserved as read cache for the virtual machine
object. Specified as a percentage of the logical size of the virtual machine disk (vmdk) object.
Reserved flash capacity cannot be used by other objects. Unreserved flash is shared fairly
among all objects. This option should be used only to address specific performance issues.
Number of failures to tolerate - Defines the number of host and device failures a virtual
machine object can tolerate. For n failures tolerated, n+1 copies of the virtual machine object
are created and 2*n+1 hosts contributing storage are required.
Force provisioning - If the option is set to Yes, the object will be provisioned even if the
policy specified in the storage policy is not satisfiable by the datastore. Use this parameter in
bootstrapping scenarios and during an outage when standard provisioning is no longer
possible.
Object space reservation - Percentage of the logical size of the virtual machine disk (vmdk)
object that should be reserved, or thick provisioned when deploying virtual machines.
Disable object checksum - If the option is set to No, the object calculates checksum
information to ensure the integrity of its data. If this option is set to Yes, the object will not
calculate checksum information. Checksums ensure the integrity of data by confirming that
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each copy of a file is exactly the same as the source file. If a checksum mismatch is detected,
Virtual SAN automatically repairs the data by overwriting the incorrect data with the correct
data.
Failure tolerance method - Specifies whether the data replication method optimizes for
Performance or Capacity. If you choose Performance, Virtual SAN uses more disk space to
place the components of objects but provides better performance for accessing the objects.
If you select Capacity, Virtual SAN uses less disk space, but reduces the performance.
IOPS limit for object - Defines the IOPS limit for a disk. IOPS is calculated as the number of
IO operations, using a weighted size. If the system uses the default base size of 32KB, then a
64KB IO represents two IO operations. When calculating IOPS, read and write are considered
equivalent, while cache hit ratio and sequentially are not considered. If a disk’s IOPS exceeds
the limit, IO operations will be throttled. If the IOPS limit for object is set to 0, IOPS limits are
not enforced.
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Storage based Policy Management
Raid 5/6 (Erasure coding)
Note that there is a requirement on the number of hosts needed to implement RAID-5 or
RAID-6 configurations on VSAN.
For RAID-5, a minimum of 4 hosts are required; for RAID-6, a minimum of 6 hosts are
required.
The objects are then deployed across the storage on each of the hosts, along with a parity
calculation. The configuration uses distributed parity, so there is no dedicated parity disk.
When a failure occurs in the cluster, and it impacts the objects that were deployed using
RAID-5 or RAID-6, the data is still available and can be calculated using the remaining data
and parity if necessary.
A new policy setting has been introduced to accommodate the new RAID-5/RAID-6
configurations.
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This new policy setting is called Failure Tolerance Method. This policy setting takes two
values: performance and capacity. When it is left at the default value of performance, objects
continue to be deployed with a RAID-1/mirror configuration for the best performance. When
the setting is changed to capacity, objects are now deployed with either a RAID-5 or RAID-6
configuration.
The RAID-5 or RAID-6 configuration is determined by the number of failures to tolerate
setting. If this is set to 1, the configuration is RAID-5. If this is set to 2, then the configuration
is a RAID-6.
Storage based Policy Management - Raid 5/6 (Erasure coding)
Select Home -> Policies and Profiles -> VM Storage Policies
Select Create a New VM Storage policy
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Storage based Policy Management - Raid 5/6 (Erasure coding)
Create a new VM Storage Policy using the following information
Name : FTT=1-Raid5
Click Next
Storage based Policy Management - Raid 5/6 (Erasure coding)
Click Next on the Rule-Sets information page
Create a new Rule-Set using the following information:
Rules based on data services : VSAN Rule 1 : Number of failures to tolerate = 1 Rule 2 : Failure tolerance method = Raid-5/6 (Erasure Coding)-Capacity
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Before you click next, check out the following:
Change the Failure tolerance method = RAID-1 (Mirroring) - Performance
Review the Storage Consumption Model on the right hand side of the screen. Notice that
the Storage space that would be used would be 200 GB based on a virtual disk of 100 GB.
Now change the Failure tolerance method = Raid-5/6 (Erasure Coding)-Capacity and you
will see that the Storage space will now be reduced to 133 GB.
Click Next
Storage based Policy Management
The Storage compatibility will be determined based on the VM Storage Policy.
Here we can see that the vsanDatastore is compatible with the VM Storage Policy that we
are about to create.
Click Next
Storage based Policy Management - Raid 5/6 (Erasure coding)
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Review the VM Storage Policy Settings
Click Finish
Storage based Policy Management - Raid 5/6 (Erasure coding)
Select FTT=1-Raid5 -> Manage -> Rule-Set-1:VSAN
Here we can see the rules that make up our VM Storage Policy.
Virtual SAN Capacity - Raid 5/6 (Erasure coding )
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Select Home -> Hosts and Clusters
Select Cluster Site A -> Monitor -> Virtual SAN -> Capacity
Make a note of the capacity figures here.
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding)
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We will clone the VM called linux-micro-01a ( which currently resides on an NFS datastore )
to the VSAN Datastore and apply the VM Storage Policy ( FTT=1-Raid5 ) that we have just
created.
Right click the VM called linux-micro-01a and select Clone -> Clone to Virtual Machine
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding )
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Give the VM a name called FTT=1-Raid5
Click Next
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding)
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Select the Compute resource called Cluster Site A
Click Next
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding)
For the VM Storage Policy, select FTT=1-Raid5
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The resulting list of compatible datastores will be presented, in our case the vsanDatastore.
In the lower section of the screen we can see that the Virtual SAN storage consumption
would be 1.33 GB disk space and 0.00 B reserved Flash space.
Since we have a VM with 1 GB disk and a VM Storage Policy of Raid 5, the VSAN disk
consumption will be 1.33 GB disk.
Click Next
Click Next on the Select clone options
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding )
Click Finish
Wait for the Clone operation to complete.
Check the Recent Tasks for a status update on the Clone virtual machine task.
Clone VM to VSAN datastore - Raid 5/6 (Erasure coding)
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Once the clone operation has completed, select the VM called FTT=1-Raid5
Select Summary -> VM Storage Policies
Here we can see that the VM Storage Policy for this VM is set to FTT=1-Raid5 and the policy
is compliant.
Select Summary -> Related Objects
The VM is now residing on the vsanDatastore
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Disk Policies - FTT=1 Raid 5
Select the VM FTT=1-Raid5 -> Monitor -> Policies -> Hard Disk 1 -> Physical Disk Placement
Notice with this VM Storage Policy, we have a Raid 5 disk placement, made up of 4
Components.
There is one component residing on each host in the Cluster.
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Virtual SAN Capacity - Raid 5/6 (Erasure coding)
To allow administrators to track where the storage consumption is occurring a brand new
capacity view has been introduced with VSAN 6.2.
Select Cluster Site A -> Monitor -> Virtual SAN -> Capacity
If we focus on the Capacity Overview first of all, we can see the full size of the VSAN
datastore. This is approximately 160 GB in size. We can also see Deduplication and
compression overhead.
The amount of space Used – Total on the VSAN datastore refers to how much space has
been physically written (as opposed to logical size). This is a combination of Virtual disks, VM
home objects, Swap objects, Performance management objects and Other items that may
reside on the datastore. Other items could be ISO images, unregistered VMs, or templates,
for example.
The Deduplication and Compression overview on the top right gives administrators an idea
around the space savings and deduplication ratio that is being achieved, as well as the
amount of space that might be required if an administrator decided that they wanted to
disable the space efficiency features on VSAN and re-inflate any deduplicated and
compressed objects.
The space savings ratio increases with the more “similar” VMs that are deployed.
This is telling us that without deduplication and compression, it would have required ~ 9.5 GB
of capacity to deploy the current workloads. With deduplication and compression, we’ve
achieved it with ~ 4.25 GB.
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Virtual SAN Capacity - Raid 5/6 (Erasure coding)
Select Cluster Site A -> Monitor -> Virtual SAN -> Capacity
Towards the bottom of the Capacity Screen, we will get a breakdown of the objects.
Group by Object Types:
Performance management objects: Capacity consumed by objects created for storing
performance metrics when Performance service is enabled
File system overhead: Any overhead taken up by the on-disk file system (VirstoFS) on the
capacity drives, which is neither attributed to deduplication, compression or checksum
overhead. When deduplication and compression is enabled, file system overhead is increased
10X to reflect the increase in the logical size of the VSAN datastore.
Deduplication and compression overhead: Overhead incurred to get the benefits of
deduplication and compression. This includes the associated mapping table, hash tables, and
other mechanisms required for deduplication and compression.
Checksum overhead: Overhead to store all the checksums. When deduplication and
compression are enabled, checksum overhead is increased 10X to reflect the increase in the
logical size of the VSAN datastore.
When a VM and a template are deployed on the VSAN datastore, more objects appear:
Virtual disks: Capacity consumed by Virtual machine disks (VMDKs) objects that reside on the
VSAN datastore
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VM home objects: Capacity consumed by VM home namespace objects (containing virtual
machine files) residing on the VSAN datastore
Swap objects: Capacity consumed by VM Swap space that reside on the VSAN datastore
Vmem – Capacity consumed by memory Objects, created as a result of taking a snapshot of
the VM which included the VM memory, or from suspended virtual machines. Note that this
will only be visible on VMs that are using a minimum of Virtual Hardware V10.
Other: Capacity consumed by VM templates, unregistered VMs, standalone VMDKs not
associated with VMs, manually created VSAN objects, manually created directories that store
ISOs for example.
Implement Raid 6 - Disk Policies
Your Lab environment is currently running a 4 Node VSAN Cluster. To implement Raid 6,
you would require a minimum of 6 hosts in the VSAN Cluster.
The VM Storage Policy will have a Failure Tolerance Method of Raid 5/6 - ( Erasure Coding )
- Capacity and the Number of failures to tolerate set to 2.
In a Raid-6 you will consume x1.5 times the storage assigned to the VM.
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Implement Raid 6 - Disk Policies
Here is an example of a VM with a Raid 6 VM Storage Policy Configuration.
In the Raid 6 configuration, there are 6 components and they are spread out across the 6
ESXi hosts in the Cluster.
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Storage based Policy Management - Object Checksum
VSAN 6.2 introduces another new feature, end-to-end software checksum, to help
customers avoid data integrity issues arising due to problems on the underlying storage
media. In VSAN 6.2, checksum is enabled by default, but may be enabled or disabled on per
virtual machine/object basis via VM storage policies.
Checksum is enabled by default as we feel customers will always want to leverage this great
new feature. The only reason one might disable it is if the application already has this
functionality included.
Brief Overview of Checksum on Virtual SAN
Checksum on VSAN is implemented using the very common cyclic redundancy check CRC-
32C (Castagnoli) for best performance, utilizing special CPU instructions on Intel processors.
Every 4KB block will have a checksum associated with it. The checksum is 5 bytes in size.
When the data is written, the checksum is verified on the same host where the data
originates to ensure that if there is any corruption in-flight over the network, it is caught. The
checksum is persisted with the data.
Scrubber mechanism
Alongside the checksum verification on read operations, VSAN also has a scrubber
mechanism which checks that the data on disk does not have any silent corruption. This
scrubber is designed to check all of the data once a year, but this can be tuned via the
advanced setting VSAN.ObjectScrubsPerYear to run more often. For instance, if you want
this to check all of the data once a week, set this to 52, but be aware that there will be some
performance overhead when this operation runs.
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Module 4 - Sparse VM Swap Object (30 Minutes)
New Sparse VM Swap Object
Those of you who have a good understanding of VSAN at this stage will know that a virtual
machine deployed on the VSAN datastore is deployed as a set of objects, and not a set of
files, which is how a VM is deployed on traditional datastores. Those objects include the VM
Home Namespace, VMDKs and of course VM Swap.
VM Swap is interesting, in that it only exists when the VM is powered on, but on VSAN it has
always been provisioned with 100% Object Space Reservation in the past.
This has some drawbacks, since it tended to consume a lot of capacity. For example, if I
deployed 100 VMs, each with 8 GB of memory, then there is 800 GB of disk provisioned for
the VM swap.
This is reserved space that I may never even use if the VM never experiences resource issues.
New Sparse VM Swap Object
To show this example, the only VM that we need powered on in our environment is the VM
called FTT=1-Raid5 that we created earlier.
If you have other VM's running, power them off now.
In the VM called FTT=1-Raid5, we can see that we have 64 MB memory assigned.
Note the ESXi host that the VM is running on, it may be different than shown here.
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New Sparse VM Swap Object
Now switch to the Capacity View.
Select Cluster Site A -> Monitor -> Virtual SAN -> Capacity
Scroll to the bottom of the Capacity View to the Used Capacity Breakdown section.
Here we can see the Swap Objects are taking around 140 MB
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New Sparse VM Swap Object
Power Off the VM called FTT=1-Raid5
As expected, there are no VM swap objects consuming space on the VSAN datastore.
Module 4 - Conclusion
In this module we showed you that in Virtual SAN 6.2, we have a way of deploying the Virtual
Machine Swap object as thin.
In environments where Virtual Machines rely on over-committing Memory, disabling the
Sparse VM Swap Object is not recommended. In this scenario, Virtual Machines will need
their swap file when there are no memory pages available.
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Module 5 - Virtual SAN Stretched Cluster (ROBO) (30 Minutes)
Virtual SAN Stretched Cluster (ROBO)
Stretched clusters extend the Virtual SAN cluster from a single site to two sites for a higher
level of availability and intersite load balancing. Stretched clusters are typically deployed in
environments where the distance between data centers is limited, such as metropolitan or
campus environments.
You can use stretched clusters to manage planned maintenance and avoid disaster scenarios,
because maintenance or loss of one site does not affect the overall operation of the cluster.
In a stretched cluster configuration, both sites are active sites. If either site fails, Virtual SAN
uses the storage on the other site. vSphere HA restarts any VM that must be restarted on the
remaining active site.
You must designate one site as the preferred site. The other site becomes a secondary or
non-preferred site. The system uses the preferred site only in cases where there is a loss of
network connection between the two active sites, so the one designated as preferred is the
one that remains operational.
A Virtual SAN stretched cluster can tolerate one link failure at a time without data becoming
unavailable. A link failure is a loss of network connection between the two sites or between
one site and the witness host. During a site failure or loss of network connection, Virtual SAN
automatically switches to fully functional sites.
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Configure Virtual SAN Stretched Cluster
Today, Virtual SAN introduces Virtual SAN for Remote Office Branch Office (ROBO), a
supported solution specifically designed and packaged to satisfy the demands of smaller
ROBO environments and suitable use cases.
Virtual SAN for ROBO is built on the foundation of Fault Domains, where in this case the
required failure zones are based on three nodes (two physical nodes and witness virtual
appliance). The witness virtual appliance is uniquely designed with the sole purpose of
providing cluster quorum services during failure events and to store witness objects and
cluster metadata information.
The use of the witness virtual appliance eliminates the requirement of a third physical node.
This is what ROBO customers were looking for as lower costs is one of the cornerstones for
ROBO use cases.
A couple of facts about the Virtual SAN Witness Virtual Appliance:
One witness virtual appliance is required per Virtual SAN ROBO cluster.
The appliance does not contribute compute nor storage resources to the cluster and it
is not able to host virtual machines.
The witness virtual appliance is exclusively available and supported ONLY for Virtual
SAN Stretched Clusters and Virtual SAN ROBO edition.
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Much like the Virtual SAN Stretched Cluster, the Virtual SAN ROBO edition is only
capable of supporting a single failure within the cluster (FTT=1) due to the support of only
three fault domains.
We have already deployed out this VSAN Witness host for you in this environment. The ESXi
host is registered as esx-07a.corp.local.
Note : The color representing the Witness host is a light blue in color to help you identify it
in your vSphere environment.
Configure Virtual SAN Stretched Cluster
Select the ESXi host called esx-07a.corp.local
Select Manage
Select Storage
Select Storage Devices
The VSAN Witness host has One Flash ( cache ) and one HDD ( capacity ).
We will use these to create the diskgroup for the VSAN Witness host.
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Configure Virtual SAN Stretched Cluster
We will now configure the Stretched Cluster or Two Host Virtual SAN cluster.
Select ROBO Cluster
Select Manage
Select Settings
Select Virtual SAN -> General
Click Configure
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Configure Virtual SAN Stretched Cluster
For the Disk Claiming, select Add disks to Storage as Manual
In the Fault Domains and Stretched Cluster section, select Configure two host Virtual SAN
cluster
Click Next
Configure Virtual SAN Stretched Cluster
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Verify that the VMkernel ports have VSAN traffic enabled.
Click Next
Configure Virtual SAN Stretched Cluster
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Select which disks should be claimed for Cache tier and for the Capacity tier in the VSAN
cluster.
The disks can be grouped by model/size or by host.
The recommended selection has been made based on the available devices in your
environment.
The number of capacity disks must be greater than or equal to the number of cache disks
claimed per host.
Click Next
Configure Virtual SAN Stretched Cluster
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Select the esx-07a.corp.local as the VSAN witness host.
The Requirements for the witness hosts are listed on the screen.
Click Next
Configure Virtual SAN Stretched Cluster
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Select the 10 GB disks for the Cache tier.
Select the 15 GB disk for the Capacity tier.
Click Next
Configure Virtual SAN Stretched Cluster
Review settings and click Finish.
Configure Virtual SAN Stretched Cluster
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Review the Recent Tasks pane.
Configure Virtual SAN Stretched Cluster
Once the tasks have completed, your VSAN Stretched Cluster will be formed.
We can see that the Stretched Cluster has been enabled, the Preferred fault domain is
called Preferred and the VSAN witness host is esx-07a.corp.local
Lower down in the screen we can see the 2 Fault Domains that were created, each fault
domain containing one ESXi host.
Virtual SAN Object Health
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Select ROBO Cluster
Select Monitor
Select Virtual SAN
Select Health
We have a new region in the Health check for Stretched Cluster.
Verify Stretched Cluster Health
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Expand the Stretched Cluster health check.
Here you will see the health checks related to VSAN Stretched Cluster.
vSphere High Availability (HA) and Distributed Resource Scheduler (DRS) settings for VSAN
Stretched Cluster
To provide availability for virtual machines in a VSAN Stretched Cluster, vSphere High
Availability (HA) needs to be configured.
This allows VMs to be restarted on the same site (with affinity rules) when there is a host
failure, or restarted on the remote site when there is a complete site failure. However, there
are certain settings that need to be configured in a specific way that are fundamental to
achieving high availability in a VSAN stretched cluster.
In this task, we will call out the VMware recommended settings and we will also explain why
we are recommending that vSphere HA be configured in this way on a VSAN Stretched
Cluster.
By following this guidance, you can be sure that your virtual machines get restarted on the
same site (maintaining read locality) when there is a component/host failure on one site. It
will also ensure that the virtual machines failover and restart on the remaining site in the
event of a complete site failure.
Clone VM to Primary Site
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Once we have the VSAN Stretched Cluster formed, we will start by getting some Virtual
Machines deployed to the VSAN Cluster. We will achieve this by cloning the linux-micro-01a
Virtual Machine.
Right click the linux-micro-01a VM and select Clone and select Clone to Virtual Machine
Clone VM to Primary Site
Give the Virtual Machine a Name, we will call it VM-Primary, this VM will reside on the
Primary Site.
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VM Name : VM-Primary
Click Next
Clone VM to Primary Site
Select the ROBO Cluster, this is where we will initially place the VM.
Click Next
Clone VM to Primary Site
Here we will apply a VM Storage Policy for the VM. We will place the VM on the
vsanDatastore.
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Select the following VM Storage Policy:
VM Storage Policy : Virtual SAN Default Storage Policy
Click Next
Clone VM to Primary Site
Click Next on the Select Clone options
Clone VM to Primary Site
Review your settings and click Finish
Clone VM to Primary Site
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We have our first VM available, let’s repeat the same process to create a second VM, called
VM-Secondary.
Clone VM to Secondary Site
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This time we will clone the VM-Primary VM.
Right click the VM-Primary VM and select Clone and select Clone to Virtual Machine
Clone VM to Secondary Site
Give the Virtual Machine a Name, we will call it VM-Secondary, this VM will reside on the
Secondary Site.
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VM Name : VM-Seondary
Click Next
Clone VM to Secondary Site
Select the ROBO Cluster, this is where we will initially place the VM.
Click Next
Clone VM to Secondary Site
Here we will apply a VM Storage Policy for the VM. We will place the VM on the
vsanDatastore.
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Select the following VM Storage Policy:
VM Storage Policy : Virtual SAN Default Storage Policy
Click Next
Clone VM to Secondary Site
Click Next on the Select Clone options
Clone VM to Secondary Site
Review your settings and click Finish
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vSphere HA and DRS settings for VSAN Stretched Cluster
We now have our 2 Virtual Machines deployed in our environment.
vSphere DRS Settings
We have already configured most of the HA and DRS settings required for a VSAN Stretched
Cluster, but we will call them out here just to show you what needs to be configured.
DRS can be setup in fully automated or partially automated mode.
For more information on setting up VSAN Cluster refer to the following link: -
http://www.vmware.com/files/pdf/products/vsan/VMware-Virtual-SAN-6.2-Stretched-Cluster-
Guide.pdf
Select ROBO Cluster - Select Manage - Select Settings - Select vSphere DRS
vSphere DRS is Turned on and in Partially Automated mode.
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VM/Host Groups
Now let’s consider DRS in VSAN stretched cluster.
The first DRS consideration is in the relationship of the VM/Host affinity rules.
DRS is needed for VM/Host affinity rules work. If DRS is not enabled, the “should” rules are
ignored. So if you want to use VM/Host affinity “should” rules, you will need DRS.
Select the cluster called ROBO Cluster
Select Manage
Select Settings
Select VM/Host Groups
Select Primary
The Primary Host Group contains the ESXi host called esx-05a.corp.local
Click Secondary
The Secondary Host Group contains the ESXi host called esx-06a.corp.local
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VM/Host Groups
Let's have a look at the VM Groups now.
Select the Primary-VM Group.
At the moment we do not have any VM's assigned to the VM Group.
Note : One thing to remember here is, if you deploy additional VM's in the VSAN Stretched
Cluster, remember to add these VM's to the VM Group so that they can be handled by DRS.
In the VM/Host Group Members, select Add
VM/Host Groups
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Select the VM called VM-Primary and click OK
VM/Host Groups
Select the Secondary-VM Group.
At the moment we do not have any VM's assigned to the VM Group
In the VM/Host Group Members, select Add
VM/Host Groups
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Select the VM called VM-Secondary and click OK
VM/Host Groups
Verify that the VM-Secondary VM is in the Secondary-VM VM Group.
VM-Host Rules
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Let's have a look at the VM/Host Rules.
Select the PrimaryVMHosts rule.
Two important pieces of information here, first is the VM/Host Rule Details - "Virtual
Machines that are members of the VM Group should run on hosts that are members of the
Host Group."
Second is the Group Members, here we can see that the VM-Primary VM "should" run on the
host called esxi-05a.corp.local
Select the SeondaryVMHosts rule
Here we can see that the VM-Secondary VM "should" run on the host called esxi-
06a.corp.local
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Enabling HA in VSAN Stretched Cluster
To provide availability for virtual machines in a VSAN Stretched Cluster, vSphere HA needs to
be configured. This allows VMs to be restarted on the same site (with affinity rules) when
there is a host failure, or restarted on the remote site when there is a complete site failure.
However, there are certain settings that need to be configured in a specific way that are
fundamental to achieving high availability in a VSAN stretched cluster.
Select ROBO Cluster
Select Manage
Select Settings
Select vSphere HA
vSphere HA is currently Turned OFF, click Edit
Enabling HA in VSAN Stretched Cluster
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Select Turn On vSphere HA
Expand Failure conditions and VM response
Enabling HA in VSAN Stretched Cluster
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For the Response for Host Isolation, verify that Power off and restart VMs is selected.
Scroll down and expand Admission Control
Enabling HA in VSAN Stretched Cluster
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If we have a site failure all of our VMs may have to run on a single site, which is effectively
half of the overall cluster. To ensure that reservations can be met, we need to configure HA
to reserve 50% of resources (i.e. one site).
In the Admission Control section verify the following :
Define failover capacity by reserving a percentage of the cluster resources :
Reserved failover CPU capacity : 50% Reserved failover Memory capacity : 50%
Click OK to Turn on vSphere HA
Configure HA to respect VM to Host affinity rules
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There is one final setting that needs to be placed on the VM/Host Rules. This setting once
again defines how vSphere HA will behave when there is a complete site failure.
In this section called vSphere HA Rule Settings.
One of the settings is for VM to Host Affinity rules.
Verify that the VM to Host Affinity rules is set to vSphere HA should respect rules during
failover
This setting can be interpreted as follows:
• If there are multiple hosts on either sites, and one hosts fails, vSphere HA will try to restart
the VM on the remaining hosts on that site, maintained read affinity.
• If there is a complete site failure, then vSphere HA will try to restart the virtual machines on
the hosts on the other site. If the “must respect” option shown above is selected, then
vSphere HA would be unable to restart the virtual machines on the other site as it would
break the rule. Using a “should” rule allows it to do just that.
Power On VM's
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Power On the two VM's called VM-Primary and VM-Secondary.
What you should notice is that the VM-Primary is running on esxi-05a.corp.local and VM-
Secondary is running on esxi-06a.corp.local.
The VM/Host Rules that we have created have dictated this.
Check component allocation for VM-01
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Select VM-Primary
Select Monitor
Select Policies
Select Hard disk 1
Select Physical Disk Placement
The layout shows that the VM has been deployed correctly, with one component per fault
domain (Site) and with the witness component on the witness host (esx-07a.corp.local ).
As we can clearly see, one copy of the data resides on storage in Preferred Fault Domain, a
second copy of the data resides on storage in Secondary Fault Domain and the witness
component resides on the witness host and storage on the witness site.
VSAN Health Check
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Before we attempt any Failure Scenarios, confirm that the Health Checks have all passed.
Ignore any of the Hardware compatibility health warnings as we are running in a Virtualized environment and we do not have the VSAN Performance service enabled in this cluster.
Failure Scenario - Reboot a Single Host
Here we will simulate a Site Failure Scenario, we will reboot a single host that has one of the VM Components.
Select the ESXi host called esx-05a.corp.local and reboot it.
Select esx-05a.corp.local, right click and select Power -> Reboot
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Failure Scenario - Reboot a Single Host
Select OK to reboot the ESXi Host.
Absent Components
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Select the VM called VM-Primary
Select Monitor
Select Policies
Select Hard disk 1
Select Physical Disk Placement
After a while, as the ESXi host is rebooting, and the VM-Primary was failed over as part of a
HA event, you will see the VSAN Object on that Host will go Absent.
You need to be patient at this step. It may require refreshing the vSphere Web Client.
VSAN Health Check
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Select ROBO Cluster
Select Monitor -> Virtual SAN -> Health
Wait for the Health Check to complete.
Expand the Data health section and monitor the errors.
Expand the Network health and monitor the errors.
Expand Physical disk health and monitor the errors.
VM-Primary restarted on other Host
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Change back to the VM Summary view for the VM called VM-Primary
Notice that the VM has been powered up on the other ESXi host called esx-06a.corp.local
ESXi host fully booted
Wait for the ESXi hosts to fully boot and reconnect to the vCenter Server.
DRS - Partially Automated
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Since we have DRS in Partially Automated Mode, DRS will handle the initial placement of
virtual machines.
However any further migration recommendations will be surfaced up to the administrator to
decide whether or not to move the virtual machine.
The administrator can check the recommendation, and may decide not to migrate the virtual
machine.
If no DRS Recommendations are presented to you, click Run DRS Now.
Click Apply Recommendations
vSphere Tasks
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Select Home
Select Tasks
Here we can see the results of the Migrate virtual machine task, that migrated the VM called
VM-Primary from the Secondary Site (esx-06a.corp.local ) back to the Preferred Site (esx-
05a.corp.local).
Select Hosts and Clusters
VM-Primary migrated to other Host
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Select the VM called VM-Primary
Once the migration task has completed, the VM called VM-Primary is now running on the
ESXi host called esxi-05a.corp.local (Preferred Site)
VSAN Health Check
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Rerun the Health Check again and it should show that the tests have passed.
Module 5 - Conclusion
In this module we showed you how to create a two node VSAN Stretched Cluster with the
VSAN Witness Host. The Witness host gave us the quorum to create this 3 node VSAN
Cluster.
We covered the vSphere High Availability (HA) and Distributed Resource Scheduler (DRS)
configuration required for VSAN Stretched Cluster and finally we simulated a node failure in
the VSAN Stretched Cluster and we saw the VM restart on the other node in the cluster.
Once the original node was back on-line again, we saw that we had to migrate the VM back
to the Preferred Site. This was because of the VMware recommendation of having DRS in
Partially Automated mode.