Performance between switches

[robbyde]

Hi All,

I have some issues with file access to a server, I've pretty much ruled out our SAN (IOPS are fine) and the server so I'm moving up to the network layer and was wondering if there was a way to test traffic between switches.

We have three switches between the server and the client, the client and the server are on different IP ranges and different vlans but I was hoping for some kind of tool to verify whether there is any network latency etc.

Hopefully this makes sense?

Thanks

Rob

[Vince_Whirlwind]

The first tool to use is ping. Do a ping over an extended period of time from a host on the client VLAN to the server. You should (on the whole) see the ping reponse coming back in 1 ms for every ping identically. If you see any variation in the reponse time, then you can use ping to find out more: ping the server from within the Server VLAN. Ping from the client VLAN to a different host on the Server VLAN. Ping the client from a host in each VLAN. See any pattern?

Then you use traceroute - is it using the route you would expect it to?

The next step is to check the 3 switches:

 - check switch logs - any strange events occurring?

 - check the interfaces the traffic is using - what speed are they all running at?

 - check the port stats for the interfaces the traffic is using - any errors? If you monitor, what is the utilisation?

Assuming nothing obvious comees out of the above, you can use robocopy to test the speed of a file download - test from a host within the same VLAN as the server, test from the client VLAN.