On 2018-01-23 10:59, Ken Dibble wrote:
Client moved from old virtual 2K3 server to newer 2K12 server. They use an IT vendor to manage all of their IT setup. They connect via Terminal Services if I understand correctly. Apparently this legacy VFP application is run from the server by all users. Performance is inconsistent, with many times it getting almost frozen for some unknown reason. Other times it's fine. No good rhyme/reason standing out. A/V and other scans have the VFP app and data folders excluded (or so I'm told). For those who have worked with VFP apps in TS mode, any tips?
"IT vendor to manage..."
Is this a "cloud"-hosted service? Have they applied the Meltdown/Spectre patches? Supposedly, especially in a virtualized setting, those can really slow things down.
We have not applied any of those patches here.
We use RDP here with a virtualized Windows 2008 server. Application runs on that server, and the data (VFP tables) are on a virtualized 2012 server on the same hypervisor. It's blazingly fast, no matter where the end user is. Faster, in fact, for many users, than running it on a desktop in our building.
According to their IT vendor:
1) It's using SMB file sharing; the program runs on Client server from a remote server. (What, huh???) 2) They did not apply those patches and won't be for awhile. 3) RDP is not an option.
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)"
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Alan Bourke -
mbsoftwaresolutions＠mbsoftwaresolutions.com