I don't know how much control you have over the environment but:

"We recently had a customer where we implemented a Windows 2012R2, Citrix 
XenApp 7.5 environment to replace a Windows Vista/2008 client server 
environment. After implementing the new Citrix XenApp environment the customer 
found a strange phenomenon where several applications where performing slower 
on the new XenApp servers then on the Vista workstations.
When we ran several tests on the environment and found that on a server with 
only the OS installed the applications worked fine. But after installing the 
terminal server environment and the applications the applications that where 
using FoxPro databases (e.g. Accountview, Caseware etc.) where running 
significantly slower andcrashing more often  than on the old Vista workstation 
environment when performing specific functions inside the applications.
The customer then did a installer by installer implementation of the Citrix 
server while testing the application after each installer. During this time 
consuming test they found out that after the installation of the Citrix VDA 
agent the problem began and we could remove the VDA agent but the problem would 
still persist.
We then started calling Citrix and the application vendors to solve this issue 
and after a while we found that the problem occurs when during the VDA 
installation the Terminal Services role is installed. During the installation 
there is a settings called Disk enablefairshare that is set in the registry
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TSFairShare\Disk\EnableFairShare]
 this has a setting of 1.
 
This settings allows Windows to normalize Disk I/O for users so they all have 
their fair share of the resources. This is what caused the problem because the 
FoxPro applications require a lot of disk I/O to perform and will immediatly 
cause issues when they don’t receive data at a fast enough rate.
After changing the value to 0 the environment performed as espected!
(be aware that changing the registry can cause serious trouble, always create a 
backup!)
There is a PowerShell command you can use to check the settings at a glance:
gwmi win32_terminalservicesetting -N “root\cimv2\terminalservices”
The setting you need to search for is called:
EnableDiskFSS  (Enable Disk fair sharing)
There are also two other settings that could save your day if you disable them
EnableNetworkFSS (Enable network fair sharing)
EnableDFSS (Enable CPU fair sharing)"




-- 
  Alan Bourke
  alanpbourke (at) fastmail (dot) fm

_______________________________________________
Post Messages to: [email protected]
Subscription Maintenance: http://mail.leafe.com/mailman/listinfo/profox
OT-free version of this list: http://mail.leafe.com/mailman/listinfo/profoxtech
Searchable Archive: http://leafe.com/archives/search/profox
This message: 
http://leafe.com/archives/byMID/profox/1516724700.3290301.1245360744.25bce...@webmail.messagingengine.com
** All postings, unless explicitly stated otherwise, are the opinions of the 
author, and do not constitute legal or medical advice. This statement is added 
to the messages for those lawyers who are too stupid to see the obvious.

Reply via email to