Well, it's been a long time. The new BigV was nice and new and clean, and went well.
Then the alerts started again, system load going up into double digits for a time. Horrible.
It was looking like it might not have been the full disk encryption in itself that caused the problem. It was just a stab in the dark really.
I decided that there must have been something in all the complaints about ClamAV after all
I didn't want to stop filtering it, but what can you do, short of shipping Bytemark a barrowful of cash every month for more memory to deal with the load.
I decided (perhaps radically) that the only thing that annoyed users more than a virus, was lots of spam. Counter-intuitive perhaps, but most people can deal with a few viruses, it's heavy loads of spam that is a pain.
So I kept the spam filtering, and dropped the antivirus checking, and then added the following to stop spam from entering the system in the first place:
smtpd_client_restrictions = permit_mynetworks,
Spam has dropped to a negligible amount. System load is next to nothing. No more 'bongs' in the night.
I'm a lot more relaxed. I'd like to do proper AV filtering, but it doesn't seem necessary.