So, I have this zvol
From what I understand, it has 778GB of actual data on disk, there's 1.02T worth of snapshots, and a refreservation of 2.1T. What makes no sense to me is why the used space is calculated as the sum of all three? Why not max(used by data, reserved)+snapshots? As it is, it looks like the 2.1T reservation is essentially wasted space that I will never be able to use. I looked through the Oracle docs on reservations, so I can blow away the reservation, but it would be great to understand why is it working this way, and what it is that I am missing. :)
Code:
~# zfs list -ro space Main/Backups NAME AVAIL USED USEDSNAP USEDDS USEDREFRESERV USEDCHILD Main/Backups 5.13T 3.88T 1.02T 778G 2.10T 0
From what I understand, it has 778GB of actual data on disk, there's 1.02T worth of snapshots, and a refreservation of 2.1T. What makes no sense to me is why the used space is calculated as the sum of all three? Why not max(used by data, reserved)+snapshots? As it is, it looks like the 2.1T reservation is essentially wasted space that I will never be able to use. I looked through the Oracle docs on reservations, so I can blow away the reservation, but it would be great to understand why is it working this way, and what it is that I am missing. :)