Adding extra hard disk

[martynbez]

Hi all,

First post here and loving freenas at the moment.

Just want to ask about adding extra hard disks into a ZFS stripe. Is this possible?

 

[sjieke]

As far as I know you can't add disks to an existing vdev (ex. RAID-Z).
What you can do is add a new vdev to an existing pool.
For examply. You have created a volume of 3 disks in a RAID-Z configuration and named it "tank".
Now you want to add another 3 disks (also in RAID-Z). To do so you need to perform the exact same steps as the first one and use the same name "tank" for the volume. During the creation freenas will create a new vdev and add it to the existing volume "tank", resulting in a doubling of the available space.

There is 1 remark though: If you add disks to an existing volume, you need to use the same redundancy, because ZFS stripes the vdev's and if 1 vdev (array of 3 disks) is lost, all data of the pool is lost.

EDIT: just realised this is also mentioned in the FAQ (question 2) that 'protosd' created: FAQ

 

[martynbez]

Ok excellent. I have not put any data on the system yet so I can afford to change things if need be,