Extending a RaidZ2 volume

[shiphtfour]

Noob question here, but how exactly does the extend volume feature work? I Didn't really understand fully what was in the documentation. Right now I have a 4x3TB ZFS RaidZ2 volume. I have 2 extra 3TB drives that I am considering adding. If I use the "volume to extend" option in volume manager to add these extra 2 drives, is there any performance penalty? Would it be the same as if I had created the initial volume with all 6 drives or is it different? Thank you in advance!

 

[ben]

You cannot actually extend a RAID group. You can make new RAID groups and stripe them into the volume, but they will be their own vdev and have their own parity, etc. This is how extending a volume works in ZFS. If you wanted all the drives in a single RAID group, you needed to have added them all at the time. The only option if that's the end result you still want is to wipe the volume and rebuild it (this will lose all the data, so back it up somewhere else).

 

[Stephens]

how exactly does the extend volume feature work?

Read the "cyberjock" ZFS primer. Search for his name. The link is in the signature line of any of his posts.