In general I am against AV on a server, because the vast majority of the time it is useless. However, the very occasional time it is useful (eg. prevent a trojan jumping from server to server through your whole network) probably means that an AV engine is worthwhile.

Personally, I'd much rather the applications running on the server were configured to be secure; but that is often asking too much. If the server sits behind a firewall, and the only ports exposed are to penetration-tested applications, then an AV is pointless (and liable to cause more problems than it solves; a forced reboot is just one of them).

However, in the last few places I have worked, a "contract" is in place with the AV provider which stipulates the AV engine must be installed on every single server. No exceptions. So an AV engine on the SQL Server servers has become an inevitable pain that I have to live with.

The AV engines I have experience of, generally don't even need MDF, LDF, etc files to be excluded. They sit quietly in the background, and as long as the hardware is up to it, don't cause me many problems.

So I guess I fall into category 1.

Andy