This post could be titled as:

1. Moron
2. Don't Jump to conclusions
3. Research things appropriately
4. Think

Recently I experienced a machine that was running under some cpu pressure.  Seeing that it was QA and during a load test, we were concerned with what was taking place on the machine.  The machine was running 20-30%, not bad, but sqlservr.exe was only using 10%.  Tracking down what else was taking place on the machine was not easy.

I focused in on DLM.EXE, wow, whats this...well being a moron, not thinking, jumping to conclusions and doing improper research....caused this....

A quick search in google, showed that DLM.exe shouldn't really be running and is often used in viruses etc, so I killed it, than of course, the machine immediately crashed, crap.  Like I said, this was QA and was meant to be the playground, but regardless it's embarrasing to have a machine crash during a load test.

Now the light bulb goes off...., duh this is "Polyserve", DLM.EXE has absoultely zero to do with anything found on that google search.  DLM = Distributed Lock Manager, and is the mechanism polyserve uses to control access to the clustered file system.  DLM.exe was running high because the cluster was experiencing large amounts of i/o across many servers due to the fact that we were running the load test during the maintenance windows of the servers (dbcc's, backups, reindexes etc).

The machine crashed because DLM.exe is part of the polyserve service, killing it caused the file system to become unstable, so the server was "fenced" from the clustered environment, exactly as Polyserve is supposed to do.  Nice to see that Polyserve worked well, even when the operator is not.