This is probably a ridiculously simple question, but here goes...

I'm troubleshooting an issue where an application (SQL Server Analysis Services) becomes unavailable for anywhere from 30 to 60 seconds at a time, multiple times per day. I've run monitoring locally on the application server, and have verified that the services aren't going down at any point, which makes me suspect a network issue - either a dropped connection or something is flooding the network.

The problem is, I have no idea how to monitor the network connection between two servers on an ongoing basis. I'm a DBA - that's not my shtick ;-)

As I said, the "downtime" is very brief, so it's not like I have the opportunity to ping the AS server when I receive an alert. Is there something that I can run to monitor the connection (round-trip time, maybe) between the two boxes?


Download Wireshark. Install. Run capture on both ends, filtering by SQL Server's TCP port (1433 if the default is used) on your client and by the client's IP on the server, until you hit this downtime. Once it happens, stop the capture and analyze. There's not guarantee you'll see something with this kind of capture - if there's noise on the network of any kind, it won't be captured with this filter, so you may need to loosen it for another capture. No reason to start grabbing everything right from the beginning, better start with more restrictive filters, then expand if necessary, otherwise you'll have to deal with lots of junk.

I should warn you though that being able to understand what's wrong looking at Wireshark capture is in some ways an art. It's an incredibly powerful tool, but you need to know very well how IP networking works - otherwise you won't be able to distinguish good stuff from your problem.

  • That sounds painful. But necessary. I'll give it a whirl and let you know how it goes. – Aaron Alton Oct 20 '09 at 12:35

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