Geek115: Real World
Perils and Pitfalls of PVS
in the Enterprise
Or.. Don’t Always Do What I Did!
Who Am I?
 Citrix Technology Professional (CTP)
 Architect of multiple Fortune 100 Citrix environments
 19+ years working with Citrix products
 Author and editor
 Owner of CitrixTips.com
 Principal Consultant at Presidio
Session Content
• Large scale PVS considerations
• Gold Disk Replication Strategies
• The ever-controversial idea of a separate streaming network
• Common monitoring and logging mistakes
• Other configuration tips and tricks
Tweet about tonight’s session with the hashtag #Geek115! All slides and
notes available post presentation.
Constructing a Solid
PVS Farm
4 © 2017 Citrix | Summit 2017 | Confidential – Content in this presentation is under NDA
Let’s Talk About a Farm!
I’ve Got 96 Sites and PVS in Every One…
Gold Disks and Replication
Show of hands… who still uses Robocopy?
Here’s an example Robocopy script to get you
started:
REM Robocopy from PVS01 to PVS02
REM Deletes files from other server if not
present on local server
Robocopy D:\vDisks \\pvs02\d$\vDisks *.vhd
*.vhdx *.avhd *.avhdx *.pvp /b /mir /xf *.lok
/xd WriteCache /xo
* Source: Carl Stalhood
…But Some People Still Use DFS-R!
DFS-R can be a viable alternative for Gold Disk storage and replication! However, it is very
dependent on the number of gold disks and frequency of changes.
Customer 1
4 gold disks, monthly image
rebuild, 8 PVS servers across 3
physical sites with 3 DFS-R servers.
VS
Customer 2
35 gold disks, constant patching
of apps and OS, 12 PVS servers
across 2 physical sites
Guess which one DFS worked well for?
Finding the Best DNS Config
Make sure to apply SMB
performance tweaks
when using CIFS!
• Yes these are old, but still
applicable.
• Make sure to read the
comments section for
SMB2 and 3 tweaks
• https://www.citrix.com/b
logs/2010/11/05/provisi
oning-services-and-cifsstores-tuning-forperformance/
Set a Preferred Primary
server!
• Round-robin DFS is bad with
multiple stream servers
• Disk versions can become out
of sync
• Set the secondary DFS to fail
back to the Primary always
Use a Hub and Spoke
Design!
• Limit Vdisk updates to a single
site
• Prevents disk contention from
multiple updates to the same
version
• Citrix recommended best
practice
To Stream or Not to Stream (Separately)?
Time for another show of hands… who still uses a separate
streaming network?
For many years the recommendation from CCS was to separate your streaming traffic from the
actual client traffic. The days of 1GB NICs in the data center are generally long dead though, and
the technical reasons for using a separate NIC are now significantly limited.
When Separate Streaming NICs Goes Wrong
Real World Story….
Client was moving from XenServer to ESX 6.0 with XenDesktop 7.8.
They had ALWAYS used a streaming network and were stubborn about keeping it
“Just because.”
Images worked fine in
Private mode but
failed trying to seal
them
Images would boot and then
have massive numbers of
retries
Sometimes the whole session
would just hang and never
recover
Windows Device Identity Manager Gets Confused
But Sometimes Streaming NICS Still Make Sense
1)
2)
3)
4)
Field office scenario with 1GB NICs in their closet
Class B Streaming Network across Sites
Secure Enclave with a segregated traffic requirement
Because you like complexity and aren’t running ESX.
Monitoring Tools
14 © 2017 Citrix | Summit 2017 | Confidential – Content in this presentation is under NDA
Make Sure You Monitor!
CDFTrace Configuration:
https://support.citrix.com/article/CTX138698
Custom PVS Monitoring
My fellow CTP Sacha Thomet wrote a very nice monitor script for PVS! Check
it out here:
http://blog.appcloud.ch/happy-new-script-pvs-7-7-healthcheck/
Other Party Monitoring
• SCOM PVS monitoring with the ComTrade integration
• Tons of 3rd party monitors
• Check out ControlUp’s real time RAM cache monitoring!
Other Configuration
Tips
18 © 2017 Citrix | Summit 2017 | Confidential – Content in this presentation is under NDA
Just Use a Service Account
I’ve been at several clients who really wanted to just use
Network Services when they installed PVS. You know what I had
to say about that?
Please, please don’t.
You know what’s easier? Just using a service account!
Use Unique Services Accounts
So I talked about how a Service Account is the easier path, but
here’s something I hear all the time:
“Yes I have a Service Account.”
And that’s what they really mean… they use 1 SA for everything.
Delay-Start PVS Services
• HKLM\System\Currentcontrolset\services\BNTFTP\Parameters (for the tftp Server)
or
• HKLM\System\CurrentControlSet\Services\PVSTSB\Parameters (for the tsb server)
• values:
• InitTimeoutSec dword 1-4 seconds (default 1)
• MaxBindRetry dword 5-20 retries (default 5)
Remove System Partition
VS
https://technet.microsoft.com/en-us/library/gg441289.aspx
Disabling Task Offload
Should you still? It Depends…
https://blogs.technet.microsoft.com/onthewire/2014/01/21/tcp-offloadingchimney-rsswhat-is-it-andshould-i-disable-it/
http://blogs.vmware.com/performance/2015/06/vmxnet3-lro.html
Citrix Health Assistant
CTX207624
Thanks For Coming!
And that’s all I’ve got today!
You can find the content of these slides at http://citrixtips.com/