Since my data center move last weekend the servers seemed a touch slow. Actually once I checked the mail server I noticed it was substantially slower. With my 100kbps connection on Sunday and Monday, everything seemed slow to me. I solved that DSL problem noting that the satellite receiver didn’t have a filter on it. Once I fixed that, the site was slow, but it was useable. I still wasn’t sure that it was me.
But I got a few emails from people, so I called my network guy because I wanted him to check things. He said he’d be happy to meet me at lunch to check things since we didn’t have remote switch access (yet). We meet at lunch, me with a couple extra cables just in case. We log in and immediately see that there are tons of CRC errors coming from the switch to the firewall. He knows what it is: duplex mismatch. We open the cage, use a serial cable to connect, and see that the switch is set to 100 full and the firewall is auto. Apparently the negotiation when things don’t match drops to 10Mbps half duplex and can generate lots of CRC errors. We reset it and things are running quicker now.
The point of this editorial isn’t so much that I’m an idiot about networking or that you should check your switches and NICs to be sure that they are set to match, but more that you should know what you don’t know.
And quickly call someone in.
It’s one thing to try to figure things out yourself, work through issues and learn on the go, but you should know the limits of your knowledge. In most areas I can quickly tell when I don’t know something and should just ask. But even in SQL Server I usually have a feel within an hour if I can solve the problem or I’m out of my league. And when I am, I call support or a consultant to help.
Too often I see people beat on a problem for too long without calling in help. Sometimes they call too soon, but usually they work a problem too long because they are afraid to ask for help. Maybe they think they’ll look bad or the boss will wonder why he’s paying them. I don’t think it’s a knock against you to call for help periodically. I’ve been a DBA a long time and it hasn’t hurt me.
In any case, knowing what you don’t know is a valuable skill. A skill I’d highly recommend you learn.