VMware - Virtual SAN - IT Changes Everything
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Transcript of VMware - Virtual SAN - IT Changes Everything
© 2014 VMware Inc. All rights reserved.
VMware Virtual SANIt changes everything
Duncan Epping
Principal Architect – R&D
Virtual SAN Technical Walkthrough
1 Introduction
2 Requirements
3 Architecture
4 Configuration Walkthrough
5 Virtual Machine Provisioning Operations
2
VMware Virtual SAN
• Storage scale out architecture built into the hypervisor
• Aggregates locally attached storage from each ESXi host in a cluster
• Dynamic capacity and performance scalability
• Flash optimized storage solution
• Fully integrated with vSphereand interoperable:
• vMotion, DRS, HA, VDP, VR …
• VM-centric data operations
3
vSphere + Virtual SAN
Hard disksHard disksSSD SSD Hard disks
SSD
…
Virtual SAN Shared Datastore
• Hypervisor-Converged storage platform
Storage Policy-Based
Management
VSAN Shared
Datastore
Simplifies and Automates Storage Management
4
Per VM storage service levels from a single self-tuning datastore
Capacity
Performance
Availability
Per VM Storage Policies
Policies set based on application needs
vSphere + VSAN
SLAs
Software automates control of service levels
No overprovisioning
Less resources, less time
Easy to change
Today
5. Consume from pre-allocated bin
4. Select appropriate bin
3. Expose pre-allocated bins
2. Pre-allocate static bins
1. Pre-define storage configurations
1. Define storage policy
2. Apply policy at VM creation
VSAN
VSAN
Shared
Datastore
Resource and data service are
automatically provisioned and
maintained
✖ Overprovisioning (better safe than sorry!)
✖ Wasted resources, wasted time
✖ Frequent Data Migrations
Virtual SAN Puts The App In Charge
Simpler and automated storage management through application centric approach
5
6
Management Clusters
Use Cases
Backup and DR
Target
DMZ / Isolated
Tier 2 / Tier 3
Test / Dev / Staging
Private cloud
Virtual Desktop
ROBO
VDI
Site A Site B
vSphereVSAN
VMware Virtual SANHardware Requirements
Two Ways to Build a Virtual SAN Node
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Completely Hardware Independent
1. Virtual SAN Ready Node
…with multiple options available at GA + 30
Preconfigured server ready to use Virtual SAN…
2. Build Your Own
…using the Virtual SAN Compatibility Guide*
Choose individual components …
Flash: SSD or PCIe
SAS/NL-SAS/ SATA HDDs
Any Server on vSphere Hardware Compatibility List
HBA/RAID Controller
Hardware Requirements
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Any Server on the VMware Compatibility Guide
• SSD, HDD, and Storage Controllers must be listed on the VMware Compatibility Guide for VSAN http://vmwa.re/vsanhcl
1Gb/10Gb NIC
SAS/SATA Controllers (RAID Controllers must work in “pass-through” or RAID0” mode
SAS/SATA/PCIe
SSD
SAS/NL-SAS/SATA
HDD
At least 1
of each
ESXi Boot device: 4GB to 8GB USB/SD
Flash Based Devices
In Virtual SAN ALL write operations always go directly to the Flash tier, and most reads will come from Flash
Flash based devices serve two purposes in Virtual SAN
1. Non-volatile Write Buffer (30%)
– Writes are acknowledged when they enter prepare stage on SSD.
– Reduces latency for writes
2. Read Cache (70%)
– Cache hits reduces read latency
– Cache miss – retrieve data from HDD
Choice of hardware is the #1 performance differentiator between Virtual SAN configurations.
10
Flash Based Devices
• VMware SSD Performance Classes
– Class A: 2,500-5,000 writes per second
– Class B: 5,000-10,000 writes per second
– Class C: 10,000-20,000 writes per second
– Class D: 20,000-30,000 writes per second
– Class E: 30,000+ writes per second
• Endurance
– 10 Drive Writes per Day (DWPD) for 5 years, and
– Random write endurance up to 3.5 PB on 8KB transfer size per NAND module, or 2.5 PB on 4KB transfer size per NAND module
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Flash Capacity Sizing
The general recommendation for sizing Virtual SAN's flash capacity is to have 10% of the anticipated consumed storage capacity before the Number of Failures To Tolerate is considered
Total flash capacity percentage should be based on use case, capacity and performance requirements
– 10% is a general recommendation, could be too much or it may not be enough
Measurement Requirements Values
Projected VM space usage 50GB
Projected number of VMs 100
Total projected space consumption per VM (50% of 50GB) x 100 = 2,500 GB = 2.5 TB
Target flash capacity percentage 10%
Total flash capacity required 2.5TB x .10 = 250 GB
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Magnetic Disks (HDD)
• SAS/NL-SAS/SATA HDDs supported
– 7200 RPM for capacity
– 10000 RPM for performance
– 15000 RPM for additional performance
• NL SAS will provide higher HDD controller queue depth at same drive rotational speed and similar price point
– NL SAS recommended if choosing between SATA and NL SAS
• When doing the design, take “overhead”, “slack space” and “failures to tolerate” in to account!
13
Storage Controllers
• SAS/SATA Storage Controllers
– Pass-through or “RAID-0” mode supported
– Also sometimes referred to as “Virtual SAN SAS” or “Virtual SAN SATA”
• Performance using RAID-0 mode is controller dependent
– Check with your vendor for SSD performance behind a RAID-controller
– Disable controller cache
• Storage Controller Queue Depth matters
– Higher storage controller queue depth will increase performance
• Validate number of drives supported for each controller
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Network
• 1Gb / 10Gb supported
– 10Gb shared with NIOC for QoS will support most environments
– If 1GB then recommend dedicated links for Virtual SAN
• Jumbo Frames will provide nominal performance increase
– Enable for greenfield deployments, could lower CPU overhead
• Virtual SAN supports both VSS & VDS
– NIOC requires VDS
– Nexus 1000v – Should work but hasn't been fully tested
• Network bandwidth performance has more impact on host evacuation, rebuild times than on workload performance
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ESXi Boot Devices
What installation device to use:
– Depends on amount of host memory
– Up to 512 GB
– Use of SD/USB devices or magnetic disks as the ESXi boot supported
– 512 GB or greater
– Only supported when using a magnetic disk or solid stated disk as the ESXi boot device
16
VMware Virtual SANTechnical Characteristics and Architecture
Technical Characteristics
Virtual SAN is a cluster level feature similar to:
– vSphere DRS
– vSphere HA
– Virtual SAN
Deployed, configured and manage from vCenter through the vSphere Web Client (ONLY!).
– Radically simple
• Configure VMkernel interface for Virtual SAN
• Enable Virtual SAN by clicking Turn On
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Virtual SAN Implementation Requirements
• Virtual SAN requires:
– Minimum of 3 hosts in a cluster configuration
– All 3 host must contribute storage
• vSphere 5.5 U1 or later
– Maximum of 32 hosts
– Locally attached disks
• Magnetic disks (HDD)
• Flash-based devices (SSD)
– Network connectivity
• 1GB Ethernet
• 10GB Ethernet (preferred)
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VSAN 10GbE netw ork
esxi-01 esxi-02 esxi-03
Virtual SAN and HA/DRS Cluster
Virtual SAN Constructs and Artifacts
New Virtual SAN constructs, artifacts and terminologies:
• Disk Groups
• VSAN Datastore
• Objects
• Components
• Virtual SAN Network
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Virtual SAN Disk Groups
• Virtual SAN uses the concept of disk groups to pool together flash devices and magnetic disks as single management constructs
• Disk groups are composed of at least 1 flash device and 1-7 magnetic disks
– Flash devices are use for performance (Read cache + Write buffer)
– Magnetic disks are used for storage capacity
– Disk groups cannot be created without a flash device
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disk group disk group disk group disk group disk group
Each host: 5 disk groups max. Each disk group: 1 SSD + 1 - 7 HDDs
Virtual SAN Datastore
• Virtual SAN is an object store solution that is presented to vSphere as a file system
• The object store mounts the VMFS volumes from all hosts in a cluster and presents them as a single shared datastore
– Only members of the cluster can access the Virtual SAN datastore
– Not all hosts need to contribute storage, but its recommended
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vsanDatastore
esxi-01
disk group disk group disk group disk group
Single VSAN datastore per cluster
esxi-02 esxi-03 esxi-04
Virtual SAN Objects
• Virtual SAN manages data in the form of flexible data containers called objects. Virtual machine files are referred to as objects
• Virtual machines files are referred to as objects
– There are four different types of virtual machine objects:
• VM Home
• VM swap
• VMDK
• Snapshots
• Virtual machine objects are split into multiple components based on performance and availabilityrequirements defined in VM Storage profile
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vsanDatastore
Virtual SAN Components
• Virtual SAN components are chunks of objects distributed across multiple hosts in a cluster in order to tolerate simultaneous failures and meet performance requirements
• Virtual SAN utilizes a Distributed RAID architecture to distribute data across the cluster
• Components are distributed with the use of two main techniques:
– Striping (RAID-0)
– Mirroring (RAID-1)
• Number of component replicas andcopies created is based on the object policy definition
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raid-1
Mirror Copy Mirror Copy
ESXi Host ESXi Host
stripe-1b
stripe-1a
stripe-2b
stripe-2a
raid-0raid-0
Virtual SAN Network
• New Virtual SAN traffic VMkernel interface
– Dedicated for Virtual SAN intra-cluster communication and data replication
• Supports both Standard and Distributed vSwitch
– Leverage NIOC for QoS in shared scenarios
• NIC teaming – used for availability and not for bandwidth aggregation
• Layer 2 Multicast must be enabled on physical switches
– Much easier to manage and implement than Layer 3 Multicast
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Management Virtual Machines vMotion Virtual SAN
Distributed Switch
20 shares 30 shares 50 shares 100 shares
vmnic0 vmnic1
vmk1 vmk2vmk0
VMware Virtual SANConfiguration Walkthrough
Configure Network
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• Configure the new dedicated Virtual SAN network
– vSphere Web Client network template configuration feature.
Enable Virtual SAN
• One click configuration
– Virtual SAN configured in Automatic mode, all empty local disks are claimed by Virtual SAN for the creation of the distributed vsanDatastore
– Virtual SAN configured in Manual mode, the administrator must manually select disks to add the the distributed vsanDatastore by creating Disk Groups
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Disk Management
• Each host in the cluster creates a single or multiple disk groups which contain a combination of HDDs, and SSDs
29
Virtual SAN Datastore
• A single Virtual SAN Datastore is created and mounted, using storage from all multiple hosts and disk groups in the cluster
• Virtual SAN Datastore is automatically presented to all hosts in the cluster
• Virtual SAN Datastore enforces thin-provisioning storage allocation by default
30
Virtual SAN Capabilities
• Virtual SAN currently surfaces five unique storage capabilities to vCenter
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Number of Failures to Tolerate
• Number of failures to tolerate
– Defines the number of hosts, disk or network failures a storage object can tolerate. For “n” failures tolerated, “n+1” copies of the object are created and “2n+1” host contributing storage are required
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vsan network
vmdkvmdk witness
esxi-01 esxi-02 esxi-03 esxi-04
~50% of I/O ~50% of I/O
Virtual SAN Policy: “Number of failures to tolerate = 1”
raid-1
Number of Disk Stripes Per Object
• Number of disk stripes per object
– The number of HDDs across which each replica of a storage object is distributed. Higher values may result in better performance.
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vsan network
stripe-2b witness
esxi-01 esxi-02 esxi-03 esxi-04
stripe-1b
stripe-1a stripe-2a
raid-0raid-0
VSAN Policy: “Number of failures to tolerate = 1” + “Stripe Width =2”
raid-1
Virtual SAN Storage Capabilities
• Force provisioning
– if yes, the object will be provisioned even is the policy specified in the storage policy is not satisfiable with the resources currently available.
• Flash read cache reservation (%)
– Flash capacity reserved as read cache for the storage object. Specified as a percentage of logical size of the object.
• Object space reservation (%)
– Percentage of the logical size of the storage object that will be reserved (thick provisioned) upon VM provisioning. The rest of the storage object is thin provisioned.
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Virtual SAN I/O flow – Write Acknowledgement
vsan network
vmdkvmdk
esxi-01 esxi-02 esxi-03 esxi-04
VSAN mirrors write IOs to all active mirrors, these are acknowledged when they hit the flash buffer!
witness
Destaging to HDD is done independently between hosts.
raid-1
VSAN IO flow – Reads
vsan network
witness
esxi-01 esxi-02 esxi-03
Read Cache
Write Buffer
Magnetic Disks
Read Cache
Write Buffer
Magnetic Disks
VSAN track of where IO resides and reads from where located
Read block 1 and 2.Block 1 is owned by
esxi-01 and block 2 by esxi-03.
vmdk vmdk
1MB(1)
1MB(2)
VMware Virtual SANVirtual Machine Provisioning Operations
Virtual Machine Provisioning Operations
• All VM provisioning operation include access to VM Storage Policies
38
Virtual Machine Provisioning Operations
• If the Virtual SAN Datastore understands the capabilities in the VMStorage Policy, it will be displayed as a matching resource
39
Virtual Machine Provisioning Operations
– If the VSAN Datastore can satisfy the VM Storage Policy, the VM Summary tab will display the VM as compliant
– If not, due to failures, or the force provisioning capability, the VM will be shown as non-compliant
40
Virtual Machine Policy Management
• Modify VM performance, capacity, and availability requirements withoutdowntime
41
Maintenance Mode – planned downtime
3 Maintenance mode options:
Ensure accessibility
Full data migration
No data migration
VMware Virtual SANSummarizing
44
Installs in two clicks
Managed from vSphere Client
Policy-based management
Self-tuning and elastic
Deep integration with VMware stack
Radically Simple
Embedded in vSphere kernel
Flash-accelerated
Matches the VDI density of all flash array
Best price/performance
100 kazillion IOps
High Performance Lower TCO
Eliminates large upfront investments (CAPEX)
Grow-as-you-go (OPEX)
Flexible choice of industry standard hardware
Does not require specialized skills
Virtual SAN Key Benefits
Don’t forget… ;-)
45