{"id":82,"date":"2015-08-18T20:45:12","date_gmt":"2015-08-18T18:45:12","guid":{"rendered":"http:\/\/www.gerjon.com\/?p=82"},"modified":"2016-05-07T12:15:19","modified_gmt":"2016-05-07T10:15:19","slug":"windows-2012r2-slow-and-slow-vfp-visual-foxpro-databases","status":"publish","type":"post","link":"https:\/\/www.gerjon.com\/?p=82","title":{"rendered":"Windows 2012R2 and slow VFP (Visual FoxPro database) applications"},"content":{"rendered":"

We recently had a customer where we implemented a\u00a0Windows 2012R2, Citrix XenApp 7.5 environment to replace\u00a0a Windows Vista\/2008 client server environment. After implementing the new Citrix\u00a0XenApp environment\u00a0the customer found a strange phenomenon where several applications where performing\u00a0slower on the new XenApp servers then on the Vista workstations.<\/p>\n

When we ran several\u00a0tests on the environment and found that on a server with only the OS installed the applications worked fine. But\u00a0after installing the terminal server environment and the applications the applications that where using FoxPro databases (e.g. Accountview, Caseware etc.) where running significantly slower\u00a0andcrashing more often \u00a0than on the old Vista workstation environment\u00a0when performing specific functions inside the applications.<\/p>\n

The customer then did a installer by installer implementation of the Citrix server\u00a0while 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\u00a0the VDA agent but the problem would still persist.<\/p>\n

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
\n[HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\TSFairShare\\Disk\\EnableFairShare]<\/span> this has a setting of 1.<\/p>\n

\"disable<\/a><\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

This settings allows Windows to normalize\u00a0Disk I\/O for users so they all have their fair share \ud83d\ude42 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.<\/p>\n

After changing\u00a0the value to 0 the environment performed as espected!
\n(be aware that changing the registry can cause serious trouble, always create a backup!)<\/p>\n

There is a PowerShell command you can use to check the settings at a glance:
\ngwmi win32_terminalservicesetting -N “root\\cimv2\\terminalservices”<\/span><\/p>\n

The setting you need to search for\u00a0is\u00a0called:
\nEnableDiskFSS\u00a0 (Enable Disk fair sharing)<\/p>\n

There are also two other settings that could save your day if you disable them
\nEnableNetworkFSS (Enable network fair sharing)
\nEnableDFSS (Enable CPU fair sharing)<\/p>\n

\"powershell<\/a><\/p>\n

And its also possible to change these settings via registry or PowerShell! this<\/a> article has for more information on that.<\/p>\n

Besides these settings there are several thing you can do to get more performance from your Foxpro database environment<\/p>\n

Hyper-V Generation 1 and 2 VM<\/strong><\/p>\n

If you are using Hyper-V as your Hypervisor of choice there is an option to create a Generation 1 and and a Generation 2 VM on creating the virtual machine.
\nBeware that after creation of the virtual machine this setting cannot be changed!<\/p>\n

The setting\u00a0\u2018Generation 2\u2019 for the virtual machine has some advantages e.g. SCSI support and EUFI boot. These features may cause problems with\u00a0Visual FoxPro applications bacause of the type of driverse used. For more information read this article:\u00a0Hyper-V 2012 R2: Pros and Cons of Generation 1 vs. Generation 2 VMs.\u00a0<\/a><\/p>\n

How to check what version the Virtual machine is:<\/b><\/p>\n

If you don’t know if your VM is generation 1 or generation 2 you can check this by starting the VM in Hyper-V Manager. In the status bar at the bottom of the screen you can see the version. You can also do this via Powershell. More information can be found in this article:\u00a0How do I see if a VM is Generation 1 or Generation2?<\/a><\/p>\n

Running Foxpro on an Hyper-V platform with RDS\/Citrix?<\/b><\/p>\n

So when using Foxpro applications in a Hyper-V virtualised environment and using remote desktop services\/Citrix \u00a0preferably use a generation 1 VM. this will give better performance. more information can be found in these articles:<\/p>\n