Would you provide some numbers on how fast does the scan happen minutes/GB/amount of files on average?
It's not super-fast, but it's all a function of how much processing power you can throw at it. It's running on old hardware, so it generally only runs at about 15MB/s on the storage side of things. Passable, but it certainly means that in the case of the file servers, it can certainly get in the way. I get around this by simply using lots of file servers (8 of them with never more than 1TB of space allocated, if anyone's counting), so that each one scans reasonably fast. Generally works out to about 150 files per second, but loads will make this vary.
I am debating on setting up "AV proxies" out of old hardware, then building the script to farm out to them, as it's definitely a processing power limitation at this point. Although in concept it might be compression slowing things down too. Haven't look at it much to be honest.
I thought that you're not satisfied with the backup job performance
The storage the job was running on was archival storage. The long version of the story is we bought a bunch of disks off Amazon to accommodate growth. I plugged them in, grew the luns, got everything running nicely. Monday morning I come in to find that 7 of the drives had failed, and the raid had critically failed on account of too many disk failures. Monday morning having yet to even drink some coffee, a melted array, and no disk-based backups, I was NOT a happy camper.
So I yanked all the bad drives and rebuilt the LUNs, however given that we had a capacity issue already, I kept our file servers on archival storage - it was definitely slow and definitely a bottleneck.. but it wasn't about to nuke my backups if I looked at it wrong. Basically I met my storage needs by moving archival tier up a notch.
Then, having replaced the failed drives and run them with an amount of data that could fit with even all of them failing for a bit of confidence building time, I was confident that this time we would be good to go and initiated the move back into faster storage, so that my archival tier can go back to archival.