Unable to mount cache pool after trying to remove a device from it.

[SGAShepp]

So I put it in raid 1 mode, fully balanced, then stopped the array and removed it. When I started the array it said something like "unmounable or no file system". So I stopped again are added it back. Worked, back at square one.

 

The next time I read to use the btrfs remove command. So I just tried to remove the one drive again, let it do it's thing for awhile til it completed, then again stopped the array and removed it from the pool. Again, "unmountable or no file system".

 

Problem is, THIS time when I added it back, it's still unmountable.

 

Looking through the logs I found two things that might me relevant. This:

 

Jul  6 20:39:45 CyprusSrv kernel: BTRFS info (device nvme0n1p1): device deleted: /dev/nvme3n1p1 

(when i used the command to delete that device from the pool).

 

And this:
 

Jul  6 20:40:55 CyprusSrv emhttpd: shcmd (2317): mount -t btrfs -o noatime,space_cache=v2 -U acda611c-011e-41b8-98fd-dc6054483acb /mnt/nvme_cache
Jul  6 20:40:55 CyprusSrv root: mount: /mnt/nvme_cache: wrong fs type, bad option, bad superblock on /dev/nvme3n1p1, missing codepage or helper program, or other error.

 

Maybe I'm actually going crazy but the docs seem spotty on exactly how to removing a drive, and I got different answers while searching.

Thanks for any help guys.

 

 

Edit: Edited title to be a little more clear, and added more information

 

cyprussrv-diagnostics-20230706-2045.zip

Edited July 7, 2023 by SGAShepp

[JorgeB]

Post the output of

btrfs fi show

 

[SGAShepp]

Sure thing.

 

:~# btrfs fi show
Label: none  uuid: e4beedf9-3a0d-4ff0-81ad-6f00dd4d38f5
        Total devices 2 FS bytes used 1.57TiB
        devid    1 size 931.51GiB used 805.00GiB path /dev/sdd1
        devid    2 size 931.51GiB used 804.06GiB path /dev/sdc1

Label: none  uuid: acda611c-011e-41b8-98fd-dc6054483acb
        Total devices 3 FS bytes used 276.14GiB
        devid    1 size 931.51GiB used 184.03GiB path /dev/nvme0n1p1
        devid    2 size 931.51GiB used 186.00GiB path /dev/nvme1n1p1
        devid    3 size 931.51GiB used 185.03GiB path /dev/nvme2n1p1

 

Sorry for the delay, Miss your post last night and worked today.

 

Thanks for the help!

[SGAShepp]

Hmm. Reading that output suggests the removal process did work.

 

So, I tried to remove /dev/nvme3n1p1 from the pool again and it worked this time. The only difference is that I set it to "unassigned" first, started the array, it mounted properly. then went back and did the "new config", setting the total devices to 3. The first time I just went straight with new config. Not even sure if that was the reason or not. but nothing else makes sense. I 100% removed the correct device the first time.
 

For future reverence, what IS the most recommended way to remove a device from a btrfs pool in unraid?

 

 

Thanks!

 

 

[JorgeB]

You can take a look here:

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=480418