So I just got a nice 15 disk dual uplink SAS DAS and I am wondering what
you guys think the best way is to allocate the disks for backing stuff
up and what is a good automated backup option for network backups.

Until now I have just done disks one by one never before using LVM but
that seems inelegant when dealing with this many disks and I am
wondering what to do especially in terms of using luks/crypto in a more
efficient manner.

I want to be able to say for instance paste a bunch of files to a mount
point and have them automatically written to whatever drives have
available space in the most speed efficient manner and if I want to
remove a drive from the pool simply be able to have the stuff
automatically copied to another drive then deleted.

Some kind of bit-rot protection would be cool as well.