Need advice troubleshooting slow network

Question

I have a client with a 3-year-old PowerEdge server, Win 2K Server Small Business, 2.3GHz processor, 1.5GB RAM, 100MB NIC, plenty of hard disk.

There are seven workstations running Win XP Pro attached through a Dell unmanaged switch. Most of the time, the workstations are doing very little. This is a dentist's office with a single dentist and one hygienist, so the network is not ever really busy.

The server has had all non-essential applications removed, such as Exchange and the IIS service. All workstations have static IPs. The database manager is migrating to SQL Server, but is fairly simplistic right now.

I have stripped all non-essential applications from the workstations (ws). Left on the workstations is Norton AV Corporate Client, the dental apps, and just about nothing else.

What I'm seeing is that when I run the dental application on the server directly, there is less than a one second delay getting patient data from the DB. I am retrieving about 15 x-rays (low res) for the patient.

When I run the application on a workstation (the application is local to the ws,) I clock a five second delay. Delays are more for other functions, such as posting payments, but I can't test those.

The corker is that, if I increase the priority of the x-ray retrieval software on he ws, I get the one-second delay. However, that is not a viable solution for a number of reasons. (Man, I wish Windows allowed us to set priorities for programs!)

I have looked at many things, including the switch. I took it out of the equation and got the same result. I shut off a large transformer that is about 10 feet from the server. No joy.

On the workstations, I have shut off almost all services with no improvement.

I have run online scans on all PCs and the server.

What else should I try?

Thank you in advance!

- Sid

jmwills · Answer

Well, the first thing that came to mind was interference of some sort especially in a dentist office with x-rays or the like. Just for kicks, have you tried another switch? I mean something like a cheap 5 port Linksys model (~$35)?

All updates on the server? How about trying another NIC?

sid_plait · Answer

I isolated the switch already, and I took EMI out of the equation. I haven't tried a new NIC yet, though. I'll do that today and report back. Thanks for the advice! - Sid

sid_plait · Answer

Well, it wasn't the NIC. I am going to go in this weekend and hook my laptop up directly to the server's NIC without a switch, load the dental software, and see what happens. Any other suggestions?

jmwills · Answer

I would also try (if you can) to run  a separate cable along the floor outside the walls (a new line from each station to the server one at a time) just to isolate the CAT5 inside the walls.  Other than that, I'd blow out the network and start over.  Anything strange looking in the Event viewer on the server?

sid_plait · Answer

Hmmm. Rereading your last post - what did you mean when you said 'blow out the network?'

sid_plait · Answer

Nothing strange in the event viewer. I've tried separate cables.

I am so out of clues. I rebuilt one of the workstations about a month ago, but that station still has the problem.

Sometimes I feel like the server is the issue, sometimes the workstations. I no longer suspect the network.

The one odd clue is that, when the priorities of the programs are raised on the workstation, everything seems to run quickly, including data posting to the database and screen painting (the time it takes to request data and the time it shows up on the screen.) But, unfortunately, that doesn't isolate either the server or workstation.

What I really need is another set of eyes to watch the server while I request and post data. I'll probably need to call in another consultant this week to help.

Thanks for the ideas. Keep 'em coming, please!

- Sid

jmwills · Answer

Uninstall all the NIC cards reboot and let them re-install.  But I like using a surface cable idea better, at least you can isolate each machine individually that way.

sid_plait · Answer

New news. It ain't the NICs, the workstations, or the server's RAM.

I ran a crossover cable from the server to my laptop, unhooked the server from the network, installed the dental software on the laptop, and ran it. The same delays occurred.

The server has 1.5GB RAM. I removed two 512MB sticks and ran the software again. What took one second to display on the server and 5 seconds to display on the workstations took over 7 seconds with .5GB RAM. I traded RAM sticks to make sure it wasn't the one stick - same result.

So. It appears to me that the issue is either something on the server interfering with network traffic, the dental software on the server, the dental software on the workstation, or a combination of things.

I doubt it's something on the server interfering with the network, because setting the priority of the application on the workstation to real time "fixes" the problem.

Here's a question for you - is there a way to set up an application so that, when it is run from another application, it's priority is set to whatever I want? That is the problem I run into if I go with setting runtime priorities.

- Sid

jmwills · Answer

A quick Google search turned this up: http://www.prioritymaster.com/   BTW, are you the same Sid from Atlanta area?

sid_plait · Answer

Thanks for the link. I'll try out that product on Monday and post back on the results. However, I'd like to solve this problem without a "quick fix." Well, if it works I think I'll walk away from this one.

I used Google on the priority issue and found several that claimed to solve my problem, but none of them worked when the app was started from within another app. Maybe this one will.

- Sid

sid_plait · Answer

Well, it turns out the problem was occurring because Symantec Antivirus Corporate Client was set on all workstations to check all traffic, even that coming from the server. I thought I had turned off all SAV client processes when I ran the initial tests, but apparently at least one survived, the one giving me all the trouble.

I discovered this after blowing away one of the PCs and reloading the OS and all applications from scratch. With a bare bones system running and the two main dental applications loaded, the response times were very good. I loaded SAV and it went into the toilet.

I set up a scanning exception for the files from the shared server directories and all is well.

I feel foolish for having missed that in my testing. However, at least it's fixed now.

Thanks for the help!

- Sid

educk · Answer

Hey Sid,   Good job on that solution, nowadays I check AV software ASAP when there is slowness--it can be quite a hog.   Also, I'm willing to betcha disabling 'opportunistic locking' at the server and on the workstations will make things fly much better.  MS has articles on what reg keys need to be hacked, and googling 'opportunistic locking' or 'oplocks' will get you some good hits.   Cheers

jmwills · Answer

What I have done SId, it set all machines to scan between 1200-1300 when everyone is at lunch.

pcmeiners · Answer

Try turning off flow control on the server NIC Search google for     disable SMB signing

splait · Answer

Thank you both!

As for opportunistic locking, I disabled that several years ago. I wish it was that easy.

Scanning is done after 6PM. No one is in the office after 4:30.

Things are still slower than the client likes, but they are better. I continue to look for other solutions, but not as vigorously as before.

PowerEdge Hardware General

Need advice troubleshooting slow network

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