Remove drive from encrypted cache pool?

[SelfSD]

I'm about to remove a drive from a 3 disk raid1c3 pool to move it to the array, but the pool is encrypted.

 

While reading the FAQ on how to remove a cache pool disk, this part got me confused:

 

On 7/18/2016 at 10:46 AM, JorgeB said:

Some Unraid releases like current stable v6.8.3 permit removing devices from non redundant pools, but this is not officially supported, the pool itself can't be encrypted and the device being removed must remain connected while the pool is balanced to the new profile, there might be other gotchas so proceed with care.

 

Does this only count for non-redundant pools or are all encrypted pools SOL when it comes to removing drives?

 

Unraid 6.9.2

Edited August 19, 2021 by SelfSD
Added unraid version

[SelfSD]

I gave it a try. The pool is up with 1 disk less and fully accessible but it did not start a balance or device delete. It's just repeating "Warning - Cache pool BTRFS missing device(s)".

 

The log says the following:

Aug 19 07:35:13 UNAS kernel: BTRFS warning (device dm-5): devid 3 uuid xxxx is missing.

Aug 19 07:35:14 UNAS emhttpd: shcmd (851638): /sbin/btrfs device delete missing /mnt/pool_name &

 

So Unraid attempted to remove the missing device, but it was not able to. I got no errors besides the device missing. I'll make a bug report about it once I have all of this down.

 

I attempted to do a manual device delete and it gave me the following error: "error removing device 'missing': unable to go below three devices on raid1c3".

 

I'm now converting it back to raid1 and will report back once it's done.

[ChatNoir]

Please attach your Diagnostics (Tools / Diagnostics) to your next post.

[JorgeB]

38 minutes ago, SelfSD said:

"error removing device 'missing': unable to go below three devices on raid1c3".

This is normal, you first needed to convert to raid1 then remove the device.

[SelfSD]

It's past the 60% mark now and I'll post the diagnostics after everything is working so you can get the whole story @ChatNoir. Don't worry, I won't restart the server between changes.

 

@JorgeB Maybe that is worth a footnote in the post since raid1cX is now an option in Unraid?

 

[JorgeB]

1 hour ago, SelfSD said:

Maybe that is worth a footnote in the post since raid1cX is now an option in Unraid?

I'll add a note that you can never go beyond minimum number of devices for the selected profile, i.e., raid1c3 and raid5 require minimum 3 devices, raid10 4 devices etc.

[SelfSD]

After converting the pool to raid1 and restarting the array, the device delete was successful!

 

Everything is running smoothly. Diagnostics attached.

unas-diagnostics-20210819-1215.zip