Slow mapped network drives?

By chris.mcquaid ·
Hi all,

A bit of a long post here I'm afraid but I wanted to give all the information!

At work we run a DOS-based business critical application. It is essentially a collection of flat files that looks at dat files for information. The application is hosted on a Windows 2003 Server, and it is accessed via mapped network drives by people in the same building, and via terminal services by people at other sites.

When everyone came into work Wednesday morning it was running excessively slow, which eventually led us to down the server for nearly two and a half hours. The company who provide and support the application were adamant that the problem must be with our servers, although I have since heard that at least one other company running it was experiencing the same problem.

We still have the same problem, and it breaks down like this:

1. Accessing from terminal services is not slow, nor does the application run slower than usual.

2. Accessing via mapped drives (even when directly on the server running the application) is extremely slow.

3. Accessing the application locally using local folders rather than mapped drives speeds up the application to its' normal speed.

Because of the above symptoms, we assumed that the problem lay in the network connection (read and write) to the mapped drives. In order to try and solve this we did the following (it was a long night!):

1. Failed over to a different server (using Double Take)

2. Uninstalled windows updates applied the previous day

3. Tried each network card on its own and teamed

4. Checked the switch (which sits about three foot from the server in question)

5. Updated the NIC drivers

6. Bypassed DNS name resolving by mapping to IP rather than host names

7. Removed and rejoined the server from the domain

At this point we're stuck in a Googling frenzy, and would appreciate any help!

Many Thanks,


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by Wizard-09 In reply to Slow mapped network drive ...

How many users are connecting to this server, we had the same issue with one of the servers at my last place, TS profiles took for ever to load, your right on the read write of the folder same issue we had we updated the nic on the server to 1g worked a treat, what nic you running, how many people are connected have you checked for bottlenecks this is a network issue i beleive.

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Users, NIC & Kaspersky

by chris.mcquaid In reply to Problem

The NIC is a 1g Broadcom. Although on average there are about 40 users accessing the application at any one time (only 10 of which access via terminal server), the problem remains exactly the same when only one user is connected.

I think we may have come across the root of the problem. We have Kaspersky deployed across the network (since January - not a new installation) and just to rule this out since we have encountered problems with it before, we uninstalled the AV from a test machine.

the result was that our application suddenly sprang into life and started working as normal. Why this conflict should suddenly appear after eleven months I don't know, and running utilities such as filemon haven't helped us understand exactly what is going on.

We have just finished excluding a number of processes and areas from scanning and detection in Kaspersky and tested the application again, but the problem remains.

We've grabbed a 30 day trial of Sophos and installed that, which causes no problems at all and the application continues to run successfully, however uninstalling our current AV and installing trial software on every client would be a logistical nightmare even if we were prepared to do it.

Currently looking at updates that Kaspersky may have applied but I think we're still a way off from a solution, so again any help would be appreciated!

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by Wizard-09 In reply to Users, NIC & Kaspersky

Well it looks like you have found the problem, as you say it might be down to some updates that have been installed.

Now looking at it from this point of view the only option you have at the min is to discontinue using the software on the machines that are having the issues until the manufacture of the AV software gives you some information on what may have been updated.

I currently use the AV software you are looking into and it's great so if you want to take that on borad if you dont get a fix for your problem from the AV company.

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by chris.mcquaid In reply to AV

We've managed to fix the above problem, by adding a number of exclusions in Kaspersky.

The exceptions included the ntvdm.exe process.

It seems that an update for the Application Analyser Utility caused this problem.

So anyway, thanks for the suggestions - much appreciated - and I thought I'd post what we've done to resolve the issue in case anyone else has a similar problem.



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