Pitfalls of antivirus programs

One has to be careful when using an antivirus application that protects computer in real time (scans files when one opens them). Here is what happened. I am working on a project for a customer of mine. For source file control we use Visual SourceSafe over VPN. I won't discuss further whether this is an ideal combination... It actually performs good enough even though the line is relatively slow. However, one day it became dead slow. By dead slow I mean half an hour to open an project and 2+ hours to get latest version. I immediately suspected Internet provider and transfer speed over Internet. Yet, this wasn't it - it was working normally on another computer of mine.

So I start thinking what did change on my computer in last week or so. After exactly 5s of deep thinking I had a revelation - I installed an antivirus system a week or so ago. Combine it with VSS over VPN and you have an unresponsive VSS client. However, the problem is not within this particular antivirus application. The problem is in the VSS itself. VSS is just a file server, meaning that everything is done on the client - actually there is no such thing as VSS server (there is some thin layer when using VSS2005 over Internet). And knowing that VSS usually produces a myriad of small files I immediately figured it out what's going on - VSS client has to check a ton of these files and each file is checked by antivirus application in real time - thus totally killing the performance (multiplying * x access on each file over VPN).

The solution was simple - I disabled real time monitor for network files and VSS started to perform normally again.

Comments (6) -

  • Mladen

    3/1/2007 9:36:08 PM | Reply

    What antivirus do you have?
    we have nod32 and a VPN to germany and it works with no problem.

  • Miha Markic

    3/1/2007 10:00:50 PM | Reply

    Yes, I installed NOD32, too. However, note that I am on slow VPN, slow mean something like 384/384Kbps.

    But let me emphasize that this isn't a NOD32 related problem. It is how antivirus applictions work in general when protecting system in real time. Actually I think that NOD32 is an excellent antivirus.

  • Peter Ritchie

    3/1/2007 11:59:02 PM | Reply

    It would be nice, in NOD32 to be able to add a network path to the exclusion list rather than disable all network checking...  Oh well.

  • Miha Markic

    3/2/2007 12:58:02 AM | Reply

    Hi Peter,

    Exactly. Actually I first tried path exclusion but it didn't work.

  • Matej

    3/2/2007 1:26:00 PM | Reply

    Or change VSS with SVN/Subversion. There is also good windows client named tortoisesvn.

  • Miha Markic

    3/2/2007 2:05:49 PM | Reply

    Hi Matej,

    Yes, I know - either subversion or Team Foundation. However, client runs the game.

Loading