Convert to ZFS Mirror

[Zythyr]

Is it possible to convert from a regular ZFS volume to a ZFS mirrored volume without losing the data?

I have 2x 3TB hard drives, but my old desktop only as 1x slot for a 3.5" hard drive. Few months later, I expect to have another desktop available with 2x 3.5" hard drive slots. If I set up FreeNAS with only 1x 3TB hard drive, can I in the future convert my freeNAS system to a mirrored volume when I have another hard drive slot available?

 

[cyberjock]

Yep. Sure can. It's the only vdev change you can make.

 

[Zythyr]

Yep. Sure can. It's the only vdev change you can make.

How can I do this? Is it command line or I can do it with the GUI interface? It is easy to do? Is there a guide on this?

It it possible to from a mirrored ZFS volume to just a regular non-mirrored volume without losing data?

 

[cyberjock]

You have to do it from the CLI I believe.

You can add and remove mirrors, but only from the CLI. If you try to do it from the GUI you'll have to wipe out your data to create a new pool with the mirror.

 

[cyberjock]

Not sure of the exact command though. You'd be wise to google the zfs commands and test it in a VM before doing it to your pool.

 

[Dusan]

Not sure of the exact command though. You'd be wise to google the zfs commands and test it in a VM before doing it to your pool.

It's:

zpool attach pool device new_device

Attaches new_device to an existing zpool device. The existing device
cannot be part of a raidz configuration. If device is not currently
part of a mirrored configuration, device automatically transforms
into a two-way mirror of device and new_device. If device is part of
a two-way mirror, attaching new_device creates a three-way mirror,
and so on. In either case, new_device begins to resilver immediately.

This can't be stressed enough: read all available documentation and test it in a VM first!

 

[Zythyr]

Thanks guys

 

[aaron.oneal]

I posted some instructions on how to do this for an encrypted drive here:
http://aarononeal.info/freenas-convert-an-encrypted-disk-to-mirror/

 

[Dave Stephens]

Aaron - thanks for your guide. Whilst I ignored the encryption bits, everything else was very useful and I've managed to convert my single disk stripe to a mirror.

 

[josecuervo]

Aaron - thanks for your guide. Whilst I ignored the encryption bits, everything else was very useful and I've managed to convert my single disk stripe to a mirror.

I need to do this also without encryption. Was it as simple as that one command line?

 

[david kennedy]

I need to do this also without encryption. Was it as simple as that one command line?

If you were using a pure "solaris" based system it would be as simple as what Dusan posted (zpool attach pool device new_device).
In freenas it is a bit more complicated as by default there are other partitions created on the disk as well (swap, etc).

From a solaris box at my disposal (single disk).

NAME STATE READ WRITE CKSUM
zones ONLINE 0 0 0
c1t0d0 ONLINE 0 0 0

If i wanted to mirror this i would just use "zpool attach zones c1t0d0 c2t0d0 " (no need to format the disk, etc).

Under freenas it looks like this

NAME STATE READ WRITE CKSUM
z01 ONLINE 0 0 0
gptid/26dea608-c80c-11e3-ab6b-080027dc6d1c ONLINE 0 0 0


There is a posting here on the forums of how to do this by copying the partition table of the original disk to the new disk first.