XenApp & XenDesktop Best Practices - UK Citrix …...© 2012 Citrix | Confidential – Do Not Distribute Introduction •Why did you create a best practices document? •What is a

May, 2012

XenApp & XenDesktop

Best Practices

Andy Baker & Thomas Berger

© 2012 Citrix | Confidential – Do Not Distribute

Introduction

• Why did you create a best practices

document?

• What is a best practice anyway?

ᵒ Appropriate at least 80% of the time

ᵒ Provides a good starting point

• Where do the best practices come from?

ᵒ Lessons learned

ᵒ Engineering

ᵒ Testing

ᵒ Customer feedback

Desktops

Users

Applications

Personalization

Access

Hardware

Control

Best Practices Top 10


#1: Scale Up or Out?

• There are many components: ᵒ Hardware & appliances

ᵒ Infrastructure servers

ᵒ XenApp servers

• There’s a lot to consider: ᵒ Available space

ᵒ Cooling & power capacity

ᵒ Hardware & maintenance costs

ᵒ Single points of failure

ᵒ Too many eggs


#2: Hyper-threading

• Allows single physical processor to appear as two

virtual cores

• Can increase user density per VM (XenApp) and

VM density per host (XenApp and XenDesktop)

• Typical performance boost of between 20-30% -

NOT 100%!

• My not be beneficial in every situation – will

depend on workload


#3: Processor and Memory Overcommit

• XenApp ᵒ Users per core – 30 [Light], 15 [Medium], 7 [Heavy]

ᵒ 1 to 1 mapping between vCPUs and cores

ᵒ Don’t overcommit memory

• XenDesktop ᵒ Users per core - 10 [Light], 6 [Medium], 2 [Heavy]

ᵒ Careful when overcommitting memory (5-10%)

• Don’t forget the hypervisor!


#4: XenServer Pool Design

• Separate resource pools for: ᵒ Control infrastructure

ᵒ XenDesktop

ᵒ XenApp

• Maximum pool size: ᵒ 16 hosts without single image technology

ᵒ 12 hosts with PVS

ᵒ 8 hosts with MCS

• Redundancy ᵒ Enable HA

ᵒ Specify multiple servers in host connection


#5: XenServer 6.02 Optimizations

• Use processors that support nested paging and second level address translation – ᵒ Extended Page Tables (Intel)

ᵒ Rapid Virtualization Indexing (AMD)

ᵒ “Optimize for XenApp” was essentially a software implementation

• Disable power saving (Green IT) functions in BIOS

• If you have more than 50 VMs per host - increase DOM0 RAM from 752MB to

2.94GB

• Receiver Side Copy (RSC) ᵒ Enabled by Default

ᵒ Work offloaded from DOM0 to guests (increases DOM0 scalability)

ᵒ Disable for small number of network intensive VMs (e.g. Provisioning Services)


#6: Storage Best Practices

• Storage is a very complex topic ᵒ CTX118397 – Introduction to Storage Technologies

ᵒ CTX130632 – Storage Best Practices

• Make sure you understand the requirements ᵒ Storage space vs. Speed

ᵒ Track the respective Win/XS performance counters • i.e.: Physical Disk \ Disk Transfers/sec = IOPS

• Monitor disk latency at all times ᵒ <10ms = OK / 10-20ms = Warning / >20ms = Issue


#7: License Server Redundancy

• Typically a single Citrix License Server is

sufficient ᵒ Grace period of 30 days

ᵒ 5 second delay for new user sessions

• Provisioned XA servers are an exception ᵒ Licenses are cached within a local ini-file

ᵒ ini-file is updated on IMA startup

• CTX131202 describes how to redirect the ini-

file to a network share / persistent disk


#8: Antivirus Optimizations

• Optimizing AV for a virtual desktop environment is

a must.

• Follow the recommendations outlined in

CTX127030

• In addition ᵒ Disable scheduled scans (i.e. upon pattern retrieval)

ᵒ Test new pattern before rollout / stagger the rollout


#9: PVS Ports & Threads

• By default PVS uses ᵒ 20 TCP ports for streaming

ᵒ 8 Threads per port

= 160 Threads

• Every target device uses one thread

when reading from its vDisk

• No thread available = queuing = disk latency

• # of ports” x “# of threads/port” = “max active clients” ᵒ Consider HA scenarios


#10: Various Items

• Have a proper monitoring solution in place ᵒ Monitoring Guide is coming soon

• Perform Capacity Planning

• Implement a three-staged test environment at minimum ᵒ Dev/Test

ᵒ UAT

ᵒ Pre-Production

ᵒ Production

• Develop/Implement Change Management procedures

• Backup your environment / perform restore tests

Summary


Summary

• We’re constantly refining the document ᵒ Subscribe to the Citrix KB RSS feed

ᵒ Subscribe to the XD Handbook (http://bit.ly/xdhandbook)

ᵒ ..or check CTX132799 every month or so

• If you have feedback / suggestions drop us a mail ᵒ Andy Baker ([email protected])

ᵒ Thomas Berger ([email protected])

http://bit.ly/xdhandbook

mailto:[email protected]

mailto:[email protected]


Q&A

Work better. Live better.

Documents

XenApp & XenDesktop Best Practices - UK Citrix …...© 2012 Citrix | Confidential – Do Not Distribute Introduction •Why did you create a best practices document? •What is a