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Network Output Queue Length

By chaom ·
Good Evening All,
Last week, I ran perfmon on one of my Compaq Proliant file servers to see its performance. One counter in particular really caught my attention. It's the Network Output Queue Length. It consistently showed greater than four. According to Microsoft explanation, normal queue length sould be less than two. I've tried several things, with no success, to resolve the problem. I'm now turning to you for advice.
Things I've tried: Changed NIC + updated driver, new Compaq Spack,new MB Bios, added more RAM, turned of unused services.
I'm not sure what cuased the queue length so big. Any help is greatly appreciated.

Melvin Chao

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Network Output Queue Length

by shasca In reply to Network Output Queue Leng ...

Output Queue Length: Assuming this counter works, and it doesn't always work as described, what it is supposed to tell you is how many packets are being held in a queue, waiting to be sent from the network card to the network. Generally, this will be zero. But if your server is very busy, it is possible that packets might have to wait for a very short amount of time before they can be delivered. As a rule of thumb, if the output queue length exceeds 2 or more for a period of 10 minutes or so ata time, mostly likely you have a network performance problem, and this is causing a network bottleneck. The cause of this problem could lie in several areas, including a bad network card driver, a slow network card, a network problem, a hub or switch problem, and so on. Or, it may just be because your File, and or SQL Server is very, very busy, and the load is just too much for the network card or the network itself. If this is the case, either reduce the load, or get a faster network card (or add additional network cards). Wiring and Hubs can cause bottle necks too. A network Fluke device could be of great help in finding weak link in network architecture.

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