Best Practices for Virtualizing Mission Critical Applications

Christopher Kusek @cxiBlog: http://pkguild.com

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Virtualizing Tier 1 is Impossible

Maturity begets virtualization

32-bit Windows900MB Database Cache

4Kb block sizeHigh read/write ratio

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

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

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– Per VHD / VMDK Locking

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

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

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

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• 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

General Best Practices

• Best Practices for– Memory– CPU– Networking

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

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*

Clusters

• Microsoft does not support migration of running virtual machines running cluster software.– Caveat: Internal testing and customer POCs have

found no affect on operation of cluster members

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

• Yes that is my tiny head!