[OpenIndiana-discuss] fuiture small expansion of raidz1 possible?

[jason matthews]

On Feb 11, 2014, at 1:12 AM, Hans J. Albertsson <hans.j.albertsson at branneriet.se> wrote:

> Suppose I set up a raidz1 of N disks now, and fill it up, and suddenly I realize I'm going to need more space, but not enough to warrant setting up a new raidz1 of another N or more disks, it's just a minor need, so I need N+1 disks, rather than just N.

for raidz, your  pool will consist of N vdevs. each vdev consists O number of disks. the pool can only be expanded by the number of disks (N) in a vdev. all vdevs have the same number of disks. all expansion is done by adding vdevs.

in mirrors, i highly recommend mirrors, a vdev is a single disk.

> 
> Can this be done w/o losing the data on the original zpool?
> 
> And on a similar note: Suppose I have a signgle disk with data, and I decide I can just afford a raidz1 of 4 disks, so I buy 3 more.... can I somehow migrate the data on the original single disk onto a 3 disk raidz1 and then add the original disk to that raidz?

Yes, you could migrate the original data to the 3 disk zpool if the configured size of the 3 disk pool is greater than the utilized size of the single disk.
You could add to the new pool as a hot spare. Alternately, the pool has to be expanded in terms of vdevs which in this case is 3 drives.

in this scenario, using mirrors makes the most sense. 


j.