Adding drives and switching between Raid systems

[Mike77]

@danb35, thanks. Your right. Can you tell me how adding the 2TB drives to the new 4TB drives zpool wil affect the speed of the new zpool?

The initial problem was that It doesn't seem possible to ad drives with data on them to an existing VDev. The problem with 6 2TB drives of which 5 are full with data.

So I'll have to create the new zpool with the new drives, copy the data from the old drives, and then add the 6 2TB drives to a new VDev after which i can add this second VDev to the new zpool.

 

[deed]

Don't want to hijack the OP's question but I have a similar question and I thought it would be useless to open a new thread;

I'm currently running FreeNAS 9.2.1.9 with 1 vdev consisting of 2 X 3TB drives (Raid1). I currently store only about 600GB.

Now I want to add additional 2 X 3TB (so thats 4 x 3TB overall) and move the vdev to RaidZ2.

If I understand correctly, my only option is:
1. Move data outside the NAS.
2. Re-create the vdev as RaidZ2.

Am I missing anything?

Sorry if this question seems a bit too newbie or over asked, but I went over cyberjock's PDF and also the official documentation for 9.2.1, and I want to confirm before proceeding.

 

[jgreco]

You are not missing anything, sorry.

 

[deed]

Cool, thanks for the quick reply, now I feel more confident doing so ;)

 

[jgreco]

I'll reiterate that a vdev is mostly unchangeable once created, with minor caveats like capacity expansion via autoexpand or adding/removing devices from mirrors. No changes of type or RAIDZ level are possible.

 

[deed]

So that new vdev (4 X 3TB, RaidZ-2) will have to keep the same number of devices.
In the future, adding more 3TB device/s to it would be impossible. Only creating a new vdev for them ?

 

[jgreco]

In the future, adding more 3TB device/s to it would be impossible. Only creating a new vdev for them ?

Adding more devices to the vdev is impossible. Replacing them with larger drives (4, 6, 8TB) is possible and when all are replaced would result in a larger vdev if done properly.

You may add another vdev OF ANY KIND to the pool. It need not be RAIDZ2, it need not be 3TB drives. ZFS won't care. It can be a single drive vdev, but of course that compromises your data protection. The pool is as secure as its weakest vdev.

 

[deed]

Just as I thought. Thanks again @jgreco .

 

[danb35]

I'd also add that you could add your two new drives as a second mirror, and your end result would be similar: a single pool with ~ 6 TB capacity and up to two disks' redundancy. Performance would likely be better than a four-disk RAIDZ2 vdev, but the redundancy would be somewhat worse--you could only lose one disk from each mirror, rather than being able to lose any two disks in a RAIDZ2 configuration.