All I want is to encryptedly back up some directories on my home server, but nothing* really does that. I use SpiderOak at the moment, but it's not OSS.
We currently allow 1.1 PB in a single "namespace" (zpool).
There are non-obvious ways to make a petabyte-sized zpool non-scary ... but even with those employed we still utilize raidz3 and have contingencies for rollbacks.
edit: for obvious reasons, that 1.1 PB number will grow by 50% in the very near future...
It's easy enough to jam enough disks into a rack with these 90disk 4u super micro jbods. The thing that always scared me (ESP with rsync) is how do you get performant metadata for a few billion files? Or even tens of millions.
And raidz3 resilver must be horrible at those densities!
Again. Just curious. Email at jmancuso@expandrive if you feel like chatting. I know we offer a similar product, but we are about to leave zfs for the above concerns. Wouldn't mind sending some business your way.
No OSS linux client, but we do have a closed source one. CrashPlan Does work headless[1], but note that that setup out of the scope for our support team.
I can't say one way or another if the client is OSS, but I do know you can run it headless, I've done it before.
IIRC, you need to tweak a non-headless client to direct it to the headless instance (some config file to point to the server vs localhost) and everything works from there.
Look into Crashplan. Client-side encryption, unlimited versioning, never deletes files, and only $6/month for truly unlimited backup.