Mirror switch port

[joe43wv]

We've been having trouble here at work with one of our servers, so the company who manages our database software says that to do some testing we must mirror a switch port, and then plug a laptop into the mirrored port and do some testing while "sniffing" a certain port. My question is, to mirror a switch port do I just configure the empty port manually just like the switch port in question or is there a command I must type in to tell the port to mirror the first one. It's a Cisco router BTW.

[CoffeeFiend]

You need a managed switch that supports it in the first place, i.e. a Cisco with the Switched Port Analyzer ("SPAN") feature or such. Otherwise, there's other solutions like a network tap from companies like netoptics, but those aren't cheap either.

[joe43wv]

I checked the switch it's a Cisco Catalyst 4503. Not sure if that model supports what your askin, but thought I'd drop that piece of info. in as well.

[CoffeeFiend]

Yes, that switch does support it.

And this page is a good read. There's likely way more resources, haven't looked around much, and I'm not much of a IOS person either...

[joe43wv]

Thanks for the link crahak, that has some really valuable info. in it, now I'm wanting to know how to configure teh mirror ports and use wireshark to watch the traffic from a laptop.

[CoffeeFiend]

Well, hopefully you can figure it out. I never really play with IOS myself (we have a network guy for that stuff) so I'm not much help there, but I'm pretty good with wireshark.

[joe43wv]

Thanks for all your help crahak, this looks like a bigger job than what I thought, we've got a contract with aconsulting firm who does work like this when it's above and beyond our knowledge so I think I'll give them a call in the morning and see what they can do for us. The way I figure it, if something goes wrong it's their fault and not mine. LOL! Thanks again for all your help.

[CoffeeFiend]

You're welcome (not that I really helped )

Not sure if it's a recent issue (an OS problem perhaps, or caused by an update?)

Well, troubleshooting database performance can be fairly complex. And what you can do varies greatly depending on which database it is.

If I could, I'd try running the queries by hand, and see what happens (peek at their execution time and their execution plan). Or log the queries, and look at those.

Slow DB performance can be caused by so many different things... Sometimes a tiny change in a query or in a schema can make a very big difference, or other small things like tweaking an index. Again, this could be a disk or network bottleneck too...

So many possibilities. If I had experts on call for this type of problem, I'd consider giving them a call too (most people just don't have an experienced DBA, advanced sys admins and network gurus on hand)