Solved ZFS RAID0 to single disk

[JozanOfAstora]

Hi, I have a simple stripping pool composed of 2 disks.

I'd like to get one of the disks back for other uses. Is there a magic ZFS way of unstripping my data to a single disk so I can get my drive back? FreeBSD is installed on this pool btw.

 

[cracauer@]

No.

 

[yuripv79]

No.

That's not exactly true nowadays, top-level vdevs removal should be supported now.

OP, check if zpool get feature@device_removal shows that the feature is there.

 

[bgrant]

Hi, I have a simple stripping pool composed of 2 disks.

I'd like to get one of the disks back for other uses. Is there a magic ZFS way of unstripping my data to a single disk so I can get my drive back?

Since you have RAID0 (striping) I don't believe there is. ZFS can't magically combine while running the data that is spread evenly across two disks back onto one. I think you'll need to create a new single disk pool, backup/restore to the new pool (making sure you also create the boot info on the new disk), reboot successfuly to the new disk and then you have both of your original disks that you can use elsewhere.

If ZFS allowed you to delete one of your disks in the stripe set all your data would be gone. (RAID1 would be a different story).

 

[Erichans]

I'm inclined to agree with the above answer.

Hi, I have a simple stripping pool composed of 2 disks.

I'd like to get one of the disks back for other uses. Is there a magic ZFS way of unstripping my data to a single disk so I can get my drive back? FreeBSD is installed on this pool btw.

Edit: AFAIK device removal only works when there still is redundancy left in the pool. I know this can be done with mirrors; I'm not sure it can be done with RAIDZ1, RAIDZ2 or RAIDZ3.

 

[yuripv79]

If ZFS allowed you to delete one of your disks in the stripe set all your data would be gone.

No, it will not be gone, as I said above, removal was implemented quite some time ago in https://www.illumos.org/issues/7614, later ported to OpenZFS (ex-ZoL), and then to FreeBSD.

 

[bgrant]

I stand corrected. I'm impressed. That is a lot of housekeeping. I'll have to spin up an old box with a couple of disks and give it a whirl.

But, if I were the OP and had important data, I'd do a backup first..

 

[JozanOfAstora]

I see that this is not easily doable. But would it be possible then to dump the full pool to a completely new single drive, then removing the 2 raided old ones?

 

[yuripv79]

It's as easy as zpool remove <poolname> <device>, but ONLY AFTER YOU MADE A BACKUP.

 

[mer]

I see that this is not easily doable. But would it be possible then to dump the full pool to a completely new single drive, then removing the 2 raided old ones?

That would be possible I believe. Problem with striping is all devices are effectively "the disk". Some blocks get written to one, others get written to the other.
It's possible that you can do a remove, but as every one else says make sure you have a solid backup first.

 

[KAMALA]

It's as easy as zpool remove <poolname> <device>, but ONLY AFTER YOU MADE A BACKUP.

Hello,


I have a case in which I have installed PVE (ProxMox VIrtuam Env.) on 2 x1TB disk / Raid0.

Now I want to remove diks and then add it again to the same pool as mirror.

Before doing on the real server I want test it on VM but I am not able to attache the disk the pool anymore, could you please help with that?

- Pool Name: rpool

disk: sda and sdb

View attachment 20687

#zpool attach -f rpool /dev/sda3 /dev/sdb3

View attachment 20688


Thanks in advance for your help