Halifax VMUG

1© Copyright 2010 EMC Corporation. All rights reserved.

Halifax VMUGNext Generation Best Practices for Storage and VMware

Rob NourseSnr. vSpecialist (Eastern Canada)EMC [email protected]


The “Great” Protocol Debate• Every protocol can Be Highly Available, and generally, every

protocol can meet a broad performance band

• Each protocol has different configuration considerations

• Each Protocol has a VMware “super-power”, and also a “kryponite”

• In vSphere, there is core feature equality across protocols

Conclusion: there is no debate – pick what works for you!

The best flexibility comes from a combination of

VMFS and NFS


First - Key Things To Know – “A ” thru “F ”Key Best Practices for 2011


Leverage Key DocsKey Best Practices circa 2010/2011

A


Key Docs, and Storage Array Taxonomy

Key VMware Docs:• Fibre Channel SAN Configuration

Guide

• iSCSI SAN Configuration Guide

• Storage/SAN Compatibility Guide

…Understand VMware Storage Taxonomy:

• Active/Active (LUN ownership)

• Active/Passive (LUN ownership)

• Virtual Port (iSCSI only)

Highly Recommended (Canadian way of saying “mandatory”) Reading:


Key Storage Partner Docs:

• Each Array is very different. Storage varies far more vendor to vendor than servers do

• Find, read, and stay current on your array’s Best Practices Doc – most are excellent.

• Even if you’re NOT the storage team, read them – it will help you.

http://www.emc.com/collateral/hardware/solution-overview/h2529-vmware-esx-svr-w-symmetrix-wp-ldv.pdfhttp://www.emc.com/collateral/hardware/technical-documentation/h5536-vmware-esx-srvr-using-celerra-stor-sys-wp.pdfhttp://www.emc.com/collateral/software/solution-overview/h2197-vmware-esx-clariion-stor-syst-ldv.pdf

Key Docs, and Storage Array TaxonomyHighly Recommended (Canadian way of saying “mandatory”) Reading:


Setup Multipathing RightKey Best Practices circa 2010/2011

B


Understanding the vSphere Pluggable Storage Architecture


What’s “out of the box” in vSphere 4.1?[root@esxi ~]# vmware -vVMware ESX 4.1.0 build-260247 [root@esxi ~]# esxcli nmp satp listName Default PSP DescriptionVMW_SATP_SYMM VMW_PSP_FIXED Placeholder (plugin not loaded)VMW_SATP_SVC VMW_PSP_FIXED Placeholder (plugin not loaded)VMW_SATP_MSA VMW_PSP_MRU Placeholder (plugin not loaded)VMW_SATP_LSI VMW_PSP_MRU Placeholder (plugin not loaded)VMW_SATP_INV VMW_PSP_FIXED Placeholder (plugin not loaded)VMW_SATP_EVA VMW_PSP_FIXED Placeholder (plugin not loaded)VMW_SATP_EQL VMW_PSP_FIXED Placeholder (plugin not loaded)VMW_SATP_DEFAULT_AP VMW_PSP_MRU Placeholder (plugin not loaded)VMW_SATP_ALUA_CX VMW_PSP_FIXED_AP Placeholder (plugin not loaded)VMW_SATP_CX VMW_PSP_MRU Supports EMC CX that do not use the ALUA protocolVMW_SATP_ALUA VMW_PSP_RR Supports non-specific arrays that use the ALUA protocolVMW_SATP_DEFAULT_AA VMW_PSP_FIXED Supports non-specific active/active arraysVMW_SATP_LOCAL VMW_PSP_FIXED Supports direct attached devices


What’s “out of the box” in vSphere?PSPs:

•Fixed (Default for Active-Active LUN ownership models)

– All IO goes down preferred path, reverts to preferred path after original path restore

•MRU (Default for Active-Passive LUN ownership models)

– All IO goes down active path, stays after original path restore

•Round Robin– n IO operations goes down

active path then rotate (default is 1000)

HOWTO – setting PSP for a specific device (can override

default selected by SATP detected ARRAYID):

esxcli nmp device setpolicy --device <device UID> --psp

VMW_PSP_RR (check with your vendor first!)


Changing Round Robin IOOperationLimit

esxcli nmp roundrobin setconfig --device <device UID> –iops

check with your storage vendor first! This setting can cause problems on arrays. Has been validated ok, but not necessary in most cases


Effect of different RR IOOperationLimit settings

NOTE: This is with a SINGLE LUN.

This is the case where the larger IOOperationLimit

default is the worst

In a real-world environment – lots of LUNs and VMs results in decent

overall loadbalancing

Recommendation – if you can, stick with the default


What is Asymmetric Logical Unit (ALUA)?

• Many storage arrays have Active/Passive LUN ownership

• All paths show in the vSphere Client as:

– Active (can be used for I/O)– I/O is accepted on all ports– All I/O for a LUN is serviced on its

owning storage processor

In reality some paths are preferred over

others

Enter ALUA to solve this issue– Supported introduced in vSphere 4.0

SP A SP B

LUN


What is Asymmetric Logical Unit (ALUA)?

ALUA Allows for paths to be profiled–Active (can be used for I/O)–Active (non-optimized – not normally used for I/O)

–Standby–Dead

• Ensures optimal path selection/usage by vSphere PSP and 3rd Party MPPs

–Supports Fixed, MRU, & RR PSP–Supports EMC PowerPath/VE

• ALUA is not supported in ESX 3.5

SP A SP B

LUN


Understanding MPIOMPIO is based on “initiator-target” sessions – not “links”


MPIO Exceptions – Windows ClustersAmong a long list of “not supported” things:

•NO Clustering on NFS datastores

•No Clustering on iSCSI, FCoE (unless using PP/VE)

•No round-robin with native multipathing (unless using PP/VE)

•NO Mixed environments, such as configurations where one cluster node is running a different version of ESX/ESXi than another cluster node.

•NO Use of MSCS in conjunction with VMware Fault Tolerance.

•NO Migration with vMotion of clustered virtual machines.

•NO N-Port ID Virtualization (NPIV)

•You must use hardware version 7 with ESX/ESXi 4.1


PowerPath – a Multipathing Plugin (MPP)• Simple Storage manageability

– Simple Provisioning = “Pool of Connectivity”

– Predictable and consistent– Optimize server, storage, and data-

path utilization

• Performance and Scale– Tune infrastructure performance,

LUN/Path Prioritization– Predictive Array Specific Load

Balancing Algorithms– Automatic HBA, Path, and storage

processor fault recovery

• Other 3rd party MPPs:– Dell/Equalogic PSP

• Uses a “least deep queue” algorithm rather than basic round robin

• Can redirect IO to different peer storage nodes

• See this at the Dell/EqualLogic booth

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PowerPath PowerPath PowerPath PowerPath

SharedStorage


NFS Considerations


General NFS Best Practices Start with Vendor Best Practices:

– EMC Celerra H5536 & NetApp TR-3749– While these are constantly being updated, at any given time, they are

authoritative

Use the EMC & NetApp vCenter plug-ins, automates best practices

Use Multiple NFS datastores & 10GbE 1GbE requires more complexity to address I/O scaling due to

one data session per connection with NFSv3


General NFS Best Practices - Timeouts Configure the following on

each ESX server (automated by vCenter plugins):

NFS.HeartbeatFrequency = 12 NFS.HeartbeatTimeout = 5 NFS.HeartbeatMaxFailures = 10

Increase Guest OS time-out values to match

– Back up your Windows registry. – Select Start>Run, regedit– In the left‐panel hierarchy view,

double‐click HKEY_LOCAL_MACHINE> System> CurrentControlSet> Services> Disk.

– Select the TimeOutValue and set the data value to 125 (decimal).

– Note: this is not reset when VMtools are updated

Increase Net.TcpIpHeapSize (follow vendor recommendation)


General NFS Best Practices – Traditional

Ethernet switches Mostly seen with older 1GbE switching platforms

Each switch operates independently

More complex network design

Depends on routing, requires two (or more) IP subnets for datastore trafficMultiple Ethernet options based on Etherchannel capabilities and preferencesSome links may be passive standby links


General NFS Best Practices – Multi-

Switch Link Aggregation Allows two physical switches to operate as a single logical fabric

Much simpler network design

Single IP subnetProvides multiple active connections to each storage controllerEasily scales to more connections by adding NICs and aliasesStorage controller connection load balancing is automatically managed by the EtherChannel IP load-balancing policy


General NFS Best Practices – HA and Scaling

10GbE?

One VMKernel port& IP subnet

Supportmulti-switch

Linkaggr?

Use multiple links withIP hash load balancing on

the NFS client (ESX)

Use multiple links withIP hash load balancing on

The NFS server (array)

Storage needs multiplesequential IP addresses

Use multiple VMKernelPorts & IP subnets

Use ESX routing table

Storage needs multiplesequential IP addresses

Yes No

Yes


• What is an Ethernet Jumbo Frame?– Ethernet frames with more than 1500 bytes of payload (9000 is common)– Commonly ‘thought of’ as having better performance due to greater

payload per packet / reduction of packets

Should I use Jumbo Frames?– Supported by all major storage vendors & VMware– Adds complexity & performance gains are marginal with common block

sizes– FCoE uses MTU of 2240 which is auto-configured via switch and CAN

handshake• All IP traffic transfers at default MTU size

Stick with the defaults when you can

iSCSI & NFS – Ethernet Jumbo Frames


iSCSI & NFS caveat when used together• Remember – iSCSI and NFS

network HA models = DIFFERENT

– iSCSI uses vmknics with no Ethernet failover – using MPIO instead

– NFS client relies on vmknics using link aggregation/Ethernet failover

– NFS relies on host routing table

• NFS traffic will use iSCSI vmknic and results in links without redundancy

– Use of multiple session iSCSI with NFS is not supported by NetApp

– EMC supports, but best practice is to have separate subnets, virtual interfaces


Summary of “Setup Multipathing Right”• VMFS/RDMs

– Round Robin policy for NMP is default BP on most storage platforms

– PowerPath/VE further simplifies/automates multipathing on all EMC (and many non-EMC) platforms.

• Notably supports MSCS/WSFC including vMotion and VM HA

• NFS– For load balancing, distribute VMs across multiple

datastores on multiple I/O paths. Follow the resiliency procedure in the TechBook to ensure VM resiliency to storage failover and reboot over NFS


Alignment = good hygieneKey Best Practices circa 2010/2011

C


“Alignment = good hygiene”• Misalignment of filesystems results in additional

work on storage controller to satisfy IO request

• Affects every protocol, and every storage array– VMFS on iSCSI, FC, & FCoE LUNs– NFS– VMDKs & RDMs with NTFS, EXT3, etc

• Filesystems exist in the datastore and VMDK

Chunk ChunkChunk

VMFS 1MB-8MB

Array 4KB-64KB

Block

Datastore Alignment

VMFS 1MB-8MB

Array 4KB-64KB






VMFS 1MB-8MB

Array 4KB-64KB

Datastore Alignment

Chunk ChunkChunk

BlockVMFS 1MB-8MB

Array 4KB-64KB






VMFS 1MB-8MB

Array 4KB-64KB

GuestAlignment

Cluster

Chunk

Cluster

Chunk

Cluster

Chunk

Block

FS 4KB-1MB

VMFS 1MB-8MB

Array 4KB-64KB






Cluster

Chunk

Cluster

Chunk

Cluster

Chunk

BlockVMFS 1MB-8MB

Array 4KB-64KB

GuestAlignment

FS 4KB-1MB


Alignment – Best Solution: “Align VMs”• VMware, Microsoft, Citrix, EMC all agree, align partitions

– Plug-n-Play Guest Operating Systems• Windows 2008, Vista, & Win7

They just work as their partitions start at 1MB

– Guest Operating Systems requiring manual alignment• Windows NT, 2000, 2003, & XP (use diskpart to set to 1MB)• Linux (use fdisk expert mode and align on 2048 = 1MB)


Alignment – “Fixing after the fact”• VMFS is misaligned

– Occurs If you created the VMFS via CLI and not via vSphere client and didn’t specify an offset.

– Resolution:

• Step 1: Take an array snapshot/backup• Step 2: Create new datastore & migrate VMs using

SVMotion

• Filesystem in the VMDK is misaligned– Occurs If you are are using older OSes and didn’t align when you created

the guest filesystem– Resolution:

• Step 1: Take an array snapshot/backup• Step 2: Use tools to realign (all VM to be shutdown)

GParted (free, but some assembly required) Quest vOptimizer (good mass scheduling and reporting)


Leverage Free Plugins/VAAIKey Best Practices circa 2010/2011

D


“Leverage Free Plugins and VAAI” • Use Vendor plug-ins for VMware vSphere

– All provide better visibility– Some provide integrated provisioning– Some integrate array features like VM snapshots,

dedupe, compression and more– Some automate multipathing setup– Some automate best practices and remediation– Most are FREE

• VAAI – it is just “on” – With vSphere 4.1, VAAI increases VM scalability and

reduces the amount of I/O traffic sent between the host and storage system and makes “never put more than ___ VMs per datastore” a thing of the past.

– Some individual operations can be faster also (2-10x!)


KISS on LayoutKey Best Practices circa 2010/2011

E


“KISS on Layout”• Use VMFS and NFS together – no reason not to

• Strongly consider 10GbE, particularly for new deployments

• Avoid RDMs, use “Pools” (VMFS or NFS)

• Make the datastores big– VMFS – make them ~1.9TB in size (2TB – 512 bytes is the max for a single

volume), 64TB for a single filesystem– NFS – make them what you want (16TB is the max)

• With vSphere 4.0 and later, you can have many VMs per VMFS datastore – and VAAI increases this to a non-issue.

• On the array, default to Storage Pools, not traditional RAID Groups / Hypers

• Default to single extent VMFS datastores

• Default to Thin Provisioning models at the array level, optionally at the VMware level.

– Make sure you enable vCenter managed datastore alerts– Make sure you enable Unisphere/SMC thin provisioning alerts and auto-

expansion

• Use “broad” data services – i.e. FAST, FAST Cache (things that are “set in one place”)


Use SIOC if you canKey Best Practices circa 2010/2011

F


“Use SIOC if you can”• This is a huge vSphere 4.1 feature

• “If you can” equals:– vSphere 4.1, Enterprise Plus– VMFS (NFS targeted for future vSphere releases – not purely a qual)

• Enable it (not on by default), even if you don’t use shares – will ensure no VM swamps the others

• Bonus is you will get guest-level latency alerting!

• Default threshold is 30ms– Leave it at 30ms for 10K/15K, increase to 50ms for 7.2K, decrease to 10ms for

SSD– Fully supported with array auto-tiering - leave it at 30ms for FAST pools

• Hard IO limits are handy for View use cases

• Some good recommended reading:– http://www.vmware.com/files/pdf/techpaper/VMW-vSphere41-SIOC.pdf – http://virtualgeek.typepad.com/virtual_geek/2010/07/vsphere-41-sioc-and-array-

auto-tiering.html– http://virtualgeek.typepad.com/virtual_geek/2010/08/drs-for-storage.html – http://www.yellow-bricks.com/2010/09/29/storage-io-fairness/


Second – knowing when to break the rules… Top 5 Exceptions for said best practices


5 Exceptions to the rules1. Create “planned datastore designs” (rather than big pools and correct

after the fact) for larger IO use cases (View, SAP, Oracle, Exchange)– Use the VMware + Array Vendor reference architectures.– Generally the cases where > 32 HBA queue & consider > 1 vSCSI adapters– Over time, SIOC may prove to be a good approach– Some relatively rare cases where large spanned VMFS datastores make

sense

2. When NOT to used “datastore pools”, but pRDMs (narrow use cases!)– MSCS/WSFC– Oracle – pRDMs and NFS can do rapid VtoP with array snapshots

3. When NOT to use NMP Round Robin– Arrays that are not active/active AND use ALUA using only SCSI-2

4. When NOT to use array thin-provisioned devices– Datastores with extremely high amount of small block random IO – In FLARE 30, always use storage pools, LUN migrate to thick devices if

needed

5. When NOT to use the vCenter plugins? Trick question – always “yes”


Finally – a peek into the future… Amazing things we’re working on….


5 Amazing things we’re working on….1. Storage Policy

– How should storage inform vSphere of capabilities and state (and vice versa)– SIOC and Auto-Tiering complement today, how can we integrate?– How can we embed VM-level Encryption?

2. “Bolt-on” vs. “Built for Purpose” using Virtual Appliance constructs– EMC has 3 shipping virtual storage appliances (Atmos/VE, Avamar/VE,

Networker/VE)– Every EMC array is really a cluster of commodity servers with disks– What more could we do to make “bolt on value” easier this way? – “follow the breadcrumb trail”:

http://stevetodd.typepad.com/my_weblog/2010/09/csx-technology.html

3. Maturing scale-out NAS/pNFS models– Desired, not demanded in enterprise, demanded, not desired for scale-out public

cloud NAS (EMC has GA’ed pNFS, but vSphere client is still NFSv3)

4. Large-scale, long distance geo-dispersion/federation of transactional workloads

– VM Teleportation – around the world, at many sites– Geo-location to meet FISMA and other standards

5. Making Object storage act transactional – for real– Would blend best of all worlds & enable VM-level policy and enforcement.


THANK YOU

Halifax VMUG

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