We can compress to xz while the new disks arrive. I
read that it is about 24
TB, so, we can revert to gzip in the future.
PS: Yes, we are installing 24TB of disks (12x 2TB disks), but this is
raw space. To begin with, a 2TB disk is only 1,862 GB of real space.
Assuming we configure the disks as RAID 50 with two 6-disk legs, that
gives (1862*(6-1))*2 = 18,620 GB (18.2TB) usable space. We will reserve
some of this for internal use (such as backups), so the total amount
available to users will be less than that.
When budgeting for this upgrade, we assumed 5TB would be used for
user-store. In reality, there should be a lot more than this (we
originally planned to use 1TB disks); but it won't be a full 24TB.