How to remove added by mistake HDD to DataVolume

[Mladen Radev]

Hi,
I'm new here so please excuse me if this topic is already discussed but I cannot find it.

The story:
I have FreeNAS running from an year but I had three faulty drives in the chassis so finally I got new ones and I replaced them. I have two DataVolumes (one is Raid10, second is Raidz2). I rebuild the raidz volume (one of the faulty drives was in it) and everything went fine. So I made the decision to add the remaining two drives as HotSpare (one per Volume) but apparently I add one as Stripe to Data2 Volume (raidz).
My question is how to release that disk and to add it as HotSpare.
Pictures:
https://drive.google.com/open?id=0B0cQT_PpHaviWjRHeUhMbmxIV0E
https://drive.google.com/open?id=0B0cQT_PpHaviRmNUZFlNMDU0eGc

 

[Arwen]

Short answer, backup pool data2, destroy pool, re-create, restore data.

This is one of the remaining gotchas with ZFS. FreeNAS Corral, (aka 10), is supposed to have more
safety features, which could have prevented this.

Another user had this problem recently;

https://forums.freenas.org/index.php?threads/honest-mistake.50747/

To be fair to ZFS, some of the gotchas are going away. For example, originally ZFS's dataset destroy
would cause a ton of I/O to release the used data. This generally slowed down the pool so that it was
un-usable. Today, we have something called async dataset destroy, which may take longer to perform
the destroy, but still allows the pool to be usable. And even allows the pool to be exported during the
middle of the process, without loss of work already done.

 

[rs225]

The other option is to keep the drive in the pool, and upgrade it to a mirror by adding another drive. That keeps your data protected until you can backup and re-create the pool.

 

[Scharbag]

Doh...

I just added L2ARC to my production pool and I quadruple checked that I was adding the drive as L2ARC. Good to hear that Coral is putting a few more belts and suspenders in place to prevent this!!