> Now what I'm thinking of is streaming multiple concurrent jobs to a single drive

I do that. On my lan, I need to backup config files and mysql, etc on a few centos and ubuntu servers. And also my win7pro computer which has large ssds, and which takes hours to backup to an LTO4 drive on my 1G network.

Trying to schedule all that is a nightmare, so I just do it all at once. The servers are only a few gigs each, and without spooling they are interleaved with the Windows backup. But that’s fine because they are located at the beginning of the tape, and so searching for server files doesn’t take very long.

Without spooling, the tape drive runs continuously with only occasional/brief stops or changes in speed. With spooling, the drive sits idle until the cache fills, then runs until the cache is empty, then waits again. It's a 2.5 hour backup without, and it’s a 4+ hour backup with spooling, if I recall. At least that’s how it works for me.

Feature request might be a threaded cache? Not sure if that’s a correct way to describe it... deleting files as are they are recorded and fetching new files to fill in the background.

Anyway, I think it works great as is, without spooling. Best to test for yourself.

Good luck.