Best Practices for Virtualizing Mission Critical Applications

Christopher Kusek @cxiGlobal Virtualization LeadEMC ConsultingBlog: http://pkguild.com

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Housekeeping

Virtualizing Tier 1 is Impossible

Maturity begets virtualization

32-bit Windows900MB Database Cache

4Kb block sizeHigh read/write ratio

*Not officially supported*

64-bit Windows32+ GB Database Cache

8Kb block size1:1 read/write ratio

70% reduction in disk I/O

64-bit Windows32Kb block size

I/O pattern optimizationI/O reduced 50% more

Who ran first so I can run too?• United States Navy/Marine Corps – 750,000

mailboxes• University of Plymouth – 40,000 mailboxes• VMware IT – 9,000 very heavy mailboxes• University of Texas at Brownsville – 25,000

mailboxes• EMC IT – 53,000 mailboxes

Where do I start?

Virtual Exchange Start here• Refer to Support Policies,

Recommendations and Best Practice Documents

• Architect for the application, not for the virtualization solution

• Pretend like you’re doing it physically… and Just do it virtually

• Defaults unless requiring optimization!

Start Simple• Deploy VMs with similar roles on separate

hosts–MBX VMs in same DAG should not co-

locate– Deploy with VMFS or Fixed Disk VHD– Scale up and scale out– Spread your CAS around

Licensing Exchange in the Virtual!!!

• One server license is required for each running instance of Exchange Server 2010 – whether it is installed natively on a physical machine or on a virtual machine

• That’s pretty simple!

Configure Storage• Review the Exchange Calculator to

determine your memory, spindle and IOPS requirement

• Configure your storage how you would handle it physically, then present it to your VMs

• Size your MBX VHD or VMDK <2TB– Some suggest 2040GB to be on the safe

side

Configure Storage Continued• Array Snapshots for any virtualization

vendor are not supported with Exchange Server– Support and supportability needs to be

supplied by your storage vendor• Live Migration and vMotion are supported

with Exchange Server, but not with DAGs*• Do exactly the same virtually as you would

physically when it comes to allocation

Configure Storage Continued• Take advantage of “Optimized for

Virtualization” acceleration technologies by storage vendors– Storage Offloading (VAAI, ODX)– Per VHD / VMDK Locking

• Unlike in the physical world, most data stores host more than one VM so account for that IO

• Auto-tiering with small granularity (768k) can result in significant storage savings

Exchange Best Practices• Do not P2V your Exchange Servers– Build new servers virtually and move

mailboxes• Split your roles and size their CPU/Mem on

a role by role basis• Analyze performance characteristics

before and after if performing migration• Less physical servers != fewer resources

Exchange Best Practices• Size Exchange VMs to fit within NUMA

nodes for best performance• Do not over commit memory unless

absolutely required• Consider DAG for local site HA, and SRM

for site resiliency/DR• Virtual machine backup products that rely

on virtual machine snapshots are not supported

Get on the road to Virtual SQL

Virtual SQL Start here• Refer to Support Policies,

Recommendations and Best Practice Documents

• Architect for the application, not for the virtualization solution

• Pretend like you’re doing it physically… and Just do it virtually

• Defaults unless requiring optimization!

Start Simple• The average physical SQL Server uses 2

CPUs is 6% utilized, 3Gb Mem, 60% utilized, ~20 IOPS

• Light workload?– Start with 2vCPUs, 3Gb ram

• Heavy workload?– Start with 4vCPUs, 8Gb+ ram

• Really Heavy workload?– Architect as if physical in the virtual– Use a capacity planner tool to assist

Licensing SQL in the Virtual?!?• Standard, Workgroup, Enterprise per proc– You must license SQL for each virtual processor

• Standard, Workgroup per Server/CAL– You must license each virtual operating system

• Enterprise per physical proc– Licensing each physical processor entitles you

to run any number of SQL server instances• 2012 switches to per core licensing!• Unsure? Contact licensing professionals!

Virtualized SQL is blazing fast!

Configure Storage Correctly• Database LUN needs enough spindles• Log LUN needs enough spindles• Mixing sequential (logs) and random

(database) can result in random behavior– Avoid mixing workloads, refer to storage

vendor• Fixed-size VHD or Eager-Zeroed Thick

VMDK for your Database and Log volumes

Configure Storage Continued• Array Snapshots for any virtualization

vendor are not supported with SQL Server– Support and supportability needs to be

supplied by your storage vendor• Live Migration and vMotion are supported

with SQL Server• Do exactly the same virtually as you would

physically when it comes to allocation

Configure Storage Continued• Try to leverage Array Tiering and

Acceleration technologies if possible– Use Array based caching to improve

performance• Most DBs, even High IO ones are hot ~10-

15% of the database, the rest is cold IO– Automatic Tiering makes for higher

performance and higher efficiency while reducing cost

Migrating SQL• Analyze your existing environment• Perform a virtualization assessment• Pay attention to disk spindles not total

space• Easy Migration: Use converter to clone

server• Easier mgmt and provisioning: Use

Templates

Database Best Practices• Follow Microsoft Best Practices for SQL

Server• Evaluate workloads for SQL-intensive ops• Consider ScalingOut for high end

deployments• Defrag SQL Databases• Design back-end to support workload

(IOPS)• Monitor DB/Logs for Disk r/w, Disk Queues• Use Fibre-channel connectivity for storage

Configuring Physical Files• Os/App, Data, Log and TempDB on

separate spindles – Separate LUNs on single datastore will not provide IO separation

• Use RAID10 or RAID5 (read-only)– Refer to your storage vendors best

practices• Pre-size data files, do not AUTOGROW• Pre-size log files, ~10% of DB on average

Configuring TempDB• Move TempDB to dedicated LUN• # of TempDB files = # of CPU cores• All TempDB files should be equal in size• Pre-Allocate TempDB space for workload• Set file growth increment to minimize

expand• Microsoft recommends FILEGROWTH incr

10%

SQL Failover Clustering Best Practices• Failover clustering is supported with

caveats– Follow best practices guide for SQL

Clustering– Use RDMS for DB and Log volumes– Use eagerthickzeroed disks– Use separate vSCSI controller for OS and

Data– Use separate vSwitches for Public and

Heartbeat– Team NICs for network redundancy

SQL Failover Clustering Best Practices• SQL Database Mirroring (SQL 2008) or

AlwaysOn Availability Groups (2012) can provide similar levels of availability as failover clusters but without the strict requirements or vendor support issues.

• Most DBs have no failover capability not clustered. By making them virtual and letting them take advantage of vSphere HA (or the Hyper-V equivalent) adds availability not possible with physical servers

General Best Practices• Best Practices for–Memory– CPU– Networking– Operations

Memory is Key

Memory Practices• Allocate your memory based upon your

application workload• Database memory doesn’t dedupe well• Do not over subscribe mission critical

workloads• Do NOT OVER SUBSCRIBE MISSION

CRITICAL WORKLOADS– Use memory reservations for mission critical

SQL workloads to avoid memory contention issues.

Hyper-V and Memory• Hyper-V Dynamic Memory is fully

supported with SQL Server. Only SQL Server versions and editions (Enterprise and Datacenter) that support Hot Add Memory can see memory that is added by using Hyper-V Dynamic Memory

• Exchange Server doesn’t change memory on the fly – No real value to enable

VMware and Memory• Enable memory ballooning and memory

page sharing• Do not over-commit memory• Set memory reserves to match VM config– Setting reservations could limit vMotion

• Enable DRS* where supported• Avoid swapping by configuring VM with

greater than average memory usage

Can has more CPU

CPU Practices• Only allocate vCPUs which are being used– Idle vCPUs will compete for system resources

• If workload is unknown, size for fewer vCPUs– You can always add more later if reqs demand

• For Performance Critical VMs– Try to ensure total number of vCPUs assigned

to all VMs is <= total number of cores on the host

– CPU load average of <=1. If greater, add more cpu

FCoTR is the key to the future

Networking Best Practices• Separate LiveMotion/vMotion, Logging and

console traffic; or use VLAN tagging• Use a paravirtualized vNIC for high

performance workloads• Leverage 802.1q using Virtual Switch

Tagging (VST). - VST is most common configuration

• Follow networking design guidelines• Do NOT use Jumbo Frames*

Operations• Virtualizing Mission Critical Applications

should leverage Virtualization monitoring solutions like – System Center– vCenter Operations

Clusters• Microsoft does not support migration of

running virtual machines running cluster software.– Caveat*

Alignment• Ensure your VMs have their disks aligned– Boot alignment is auto in 2008, manual

in 2003– Application LUN is manual, follow

application and storage vendor best practices

Thank you!

Links if you don’t see presenter notes!• Microsoft Support Policies and Recommendations for Exchange Servers in Hardware Virtualization Environments• Exchange 2010 on VMware - Best Practices Guide• http://www.vmware.com/pdf/Virtualizing_Exchange2003.pdf• http://www.vmware.com/files/pdf/solutions/08Q4_VM_Exchange_Server_2007_VI3_WP.pdf• http://www.vmware.com/files/pdf/Exchange_2010_on_VMware_-_Best_Practices_Guide.pdf

• Microsoft Virtualization Best Practices for Exchange• HP recommended configuration for Exchange Server 2010 and Hyper-V R2 for 5,000 users• Exchange Server 2007 and Hyper-V: Best Practices Blog Post• Policies and Recommendations for Exchange Servers in  Virtualization Environments

• Refer to these great blog series which covers Exchange and VMware• http://www.clearpathsg.com/blogs/2010/07/13/exchange-2010-vsphere-4-best-practices-part-1• http://www.clearpathsg.com/blogs/2010/07/29/exchange-2010-vsphere-4-best-practices-part-2• http://www.clearpathsg.com/blogs/2011/01/13/exchange-2010-vsphere-4-best-practices-part-3

• Duncan Epping• http://www.yellow-bricks.com/2008/12/17/exchange-2007on-vmware/

• Best Practices for SQL Server with VMware• Microsoft SQL Server and VMware Virtual Infrastructure Best Practices • Running SQL in a Hyper-V Environment • Consolidation Guidance for SQL Server• High Performance SQL Server Workloads on Hyper-V• SQL Server 2008 on Hyper-V - Best Practices & Performance• Licensing SQL• Alignment

Credits• Christopher Kusek, vExpert, CISSP,

MCT• EMC Consulting• Global Virtualization Lead

• Twitter: @cxi• Blog: http://pkguild.com