Is there a way in which ZFS can be prompted to redistribute a given filesystem over the all of the disks in its zpool?
I'm thinking of a scenario where I have a fixed size ZFS volume that's exported as a LUN over FC. The current zpool is small, just two 1TB mirrored disks, and the zvol is 750GB in total. If I were to suddenly expand the size of the zpool to, say, 12 1TB disks, I believe the zvol would still effectively be 'housed' on the first two spindles only.
Given that more spindles = more IOPS, what method could I use to 'redistribute' the zvol over all 12 spindles to take advantage of them?
Best Answer
You would need to rewrite your data to the expanded zpool in order to rebalance it. Otherwise, as time passes, your writes will be distributed across the entire pool.