Extremely slow access to a database on a RAID server

mazzarioa · Post by **mazzarioa** » Thu Apr 07, 2005 2:00 pm

we have moved the VSS database to a RAID server, and the result is that the SOS Classic 4.0.2 access has become terribly slow.
I did some tests using the VSS and SOS clients, both executing on the same server as the VSS and SOS servers: I did execute "Get Latest Version" on a directory that I know is up to date: the VSS cleint took ~10 seconds, while the SOS client took 22 minutes!
I have enabled client caching on the RAID server, but looking at the network traffic it does not look like that has any effect on the operation of the SourceOffsite server.
We are running windows XP SP2
Any help will be greatly appreciated.

lbauer · Post by **lbauer** » Thu Apr 07, 2005 3:41 pm

Is the machine a dual processor? Is real-time antivirus protection running on the new machine? If so, these could be affecting SOS performance.

See this KB article for details:
http://support.sourcegear.com/viewtopic.php?t=2575

mazzarioa · Post by **mazzarioa** » Thu Apr 07, 2005 4:25 pm

The server running VSS and SOS servers is a single processor.
It turns out that the real-time antivirus protection was running on the VSS / SOS server. I disabled it and it made a HUGE difference.
Thank you very much for pointing it out.
The only strange thing is that this real-time antivirus protection (Norton Antivirus) did not affect VSS performance if accessed directly from the VSS client, it only affected SOS. Isn't that strange?

lbauer · Post by **lbauer** » Fri Apr 08, 2005 8:00 am

Although anti-virus software can affect VSS itself, I think it affects SOS more because the SOS Server is constantly writing out to a temp directory. If your anti-virus software is scanning every file written to the temp directory, then this would be a bigger performance hit for SOS than for VSS.

LarryH · Post by **LarryH** » Fri Aug 12, 2005 9:37 am

[Just reading through some old issues - I am a new SOS user]

I discovered the usual installation caveats when I installed the server, initially on a dual processor machine running Win Server 2003, then (backing off) onto a uniprocessor machine running XP Pro SP2. I am getting reasonable performance now after disabling realtime antivirus scanning, but your last post begs the question (since we would really like to continue to have antivirus protection on this machine):

what if I just exclude the SOS temp directory on the SOS server machine from realtime virus scan? Will I get pretty good performance from SOS then?

lbauer · Post by **lbauer** » Fri Aug 12, 2005 3:57 pm

We haven't done extensive testing of SOS with anti-virus software, since there are so any variables. But here are some suggestions:

The impact of anti-virus protection is not just on SOS, but on VSS as well:

http://support.microsoft.com/default.as ... roduct=vss

For best performance, make sure all of the following folders have real-time scanning
disabled:

Server:
The SOS server's temp folder, usually a subfolder of the application
folder. This includes subfolders for every client connection and is where we
"get" all files before sending them to the client. In SOS Classic 4.0 this
folder's location is configurable.

Client: (not as important as the load is now on the client machine)
Working folders

VSS Database (possibly same machine as the server):
The entire "data" folder which contains all of the VSS data in
subfolders "a"..."z".