Skip to content
View in the app

A better way to browse. Learn more.

Unraid

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

BTRFS Array Unmountable (2 drive pool, 3 drives listed)

Featured Replies

Hi! Need some help with one of my BTRFS arrays becoming unmountable. "Unsupported or no file system". 

 

I performed a filesystem check in maintenance mode, with the following result: 

 


[1/7] checking root items
[2/7] checking extents
ERROR: super total bytes 2000407674880 smaller than real device(s) size 4000805560320
ERROR: mounting this fs may fail for newer kernels
ERROR: this can be fixed by 'btrfs rescue fix-device-size'
[3/7] checking free space tree
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
Opening filesystem to check...
Checking filesystem on /dev/sdo1
UUID: 09a80e5f-82a2-4a02-89d6-4ca4016b58f7
found 882812723200 bytes used, error(s) found
total csum bytes: 762312024
total tree bytes: 1058029568
total fs tree bytes: 59916288
total extent tree bytes: 50003968
btree space waste bytes: 196698144
file data blocks allocated: 18196154212352
 referenced 865362587648

 

I tried some of the steps from this post: 

I managed to do a read-only mount and copied the files onto my array. The fix-device-size step didn't work because the device was still mounted? Sorry I'm not familiar with the technical details. But I assume it needs to be unmounted?

 

Diags attached. I upgraded to Unraid 6.12.3 very recently, from 6.10.3. The array worked fine after the upgrade, for at least 2 reboots. 

 

Any suggestions on what to do next? thanks in advance. 

 

 

homecloudv2-diagnostics-20230829-1511.zip

Edited by artkingjw

Solved by JorgeB

  • Community Expert

Something strange going since it's showing 2 devices but listing 3, post the output of:

btrfs fi show

 

  • Author
39 minutes ago, JorgeB said:

Something strange going since it's showing 2 devices but listing 3, post the output of:

btrfs fi show

 

Label: none  uuid: e2554b33-7ded-4c8c-9329-017396f8f091
        Total devices 2 FS bytes used 347.58GiB
        devid    2 size 931.51GiB used 388.03GiB path /dev/sdm1
        devid    3 size 931.51GiB used 388.03GiB path /dev/sdl1

Label: none  uuid: 09a80e5f-82a2-4a02-89d6-4ca4016b58f7
        Total devices 2 FS bytes used 822.18GiB
        devid    2 size 931.51GiB used 931.51GiB path /dev/sdk1
        devid    3 size 1.82TiB used 2.00GiB path /dev/sdo1
        devid    4 size 931.51GiB used 931.51GiB path /dev/sdn1

There should be 2 btrfs raid 1 arrays, each made of 2X 1TB SSDs. The first array 'cache' is fine, the second 'cache_n' is the problem one. 

Based on this output, it looks like it's trying to look for sdo1, a 2tb ssd, to join the pool? this drive is attached but it's not part of any array, it's not mounted. 

Edited by artkingjw

  • Community Expert
  • Solution
1 hour ago, artkingjw said:

Based on this output, it looks like it's trying to look for sdo1

Yeah, but it also mentions "Total devices 2", so there shouldn't be a third device, try physically disconnecting that device and starting the pool with the two existing ones, if it still doesn't mount post new diags after array start.

  • Author

Disconnected all drives not used in the arrays

 

btrfs check output: 


[1/7] checking root items
[2/7] checking extents
WARNING: minor unaligned/mismatch device size detected:	super block total bytes=4000805560320 found total bytes=2000407674880
WARNING: recommended to use 'btrfs rescue fix-device-size' to fix it
[3/7] checking free space tree
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
Opening filesystem to check...
Checking filesystem on /dev/sdk1
UUID: 09a80e5f-82a2-4a02-89d6-4ca4016b58f7
found 882812723200 bytes used, no error found
total csum bytes: 762312024
total tree bytes: 1058029568
total fs tree bytes: 59916288
total extent tree bytes: 50003968
btree space waste bytes: 196698144
file data blocks allocated: 18196154212352
 referenced 865362587648

 

starting the array normally allows all drives to mount.

 

here are the diags. Thanks 

homecloudv2-diagnostics-20230830-1344.zip

Edited by artkingjw

  • Community Expert
4 hours ago, artkingjw said:

starting the array normally allows all drives to mount.

That's good but btrfs check still shows an issue with the superblock, I would recommend backing up and re-formatting the pool.

  • Author
5 hours ago, JorgeB said:

That's good but btrfs check still shows an issue with the superblock, I would recommend backing up and re-formatting the pool.

Ok, if I were to reformat, I guess I could just as well replace those 1TB drives with 2TB drives if I wish? 

 

Will unraid recognize my new array as the 'same' as the old array? After I recopy all of the data back? 

I suspect not... but then I could just go to Shares and point it to the new array right? Everything should be seamless? 

Anyway, I tried fix-device-size again, and this time it worked, I no longer get that device size warning when i do a file system check. Attached are diags if relevant. First, I'm doing a scrub, just in case. Next, I'll make a copy of the data on the drive, and reformat/make a new array when able to. 

homecloudv2-diagnostics-20230830-2258.zip

Edited by artkingjw
added small update + diags

  • artkingjw changed the title to BTRFS Array Unmountable (2 drive pool, 3 drives listed)
  • Community Expert
1 hour ago, artkingjw said:

Ok, if I were to reformat, I guess I could just as well replace those 1TB drives with 2TB drives if I wish? 

Yes.

 

1 hour ago, artkingjw said:

Will unraid recognize my new array as the 'same' as the old array? After I recopy all of the data back? 

I suspect not... but then I could just go to Shares and point it to the new array right? Everything should be seamless? 

If you mean the pool yes, it would still recognize it the same, assuming same name was used.

 

1 hour ago, artkingjw said:

Anyway, I tried fix-device-size again, and this time it worked, I no longer get that device size warning when i do a file system check.

That's good, but there could still be issues if you reconnected the other device, though you can do a full wipe on it to avoid that.

  • Author
9 hours ago, JorgeB said:

If you mean the pool yes, it would still recognize it the same, assuming same name was used.

Yes, I mean, the 'cache_n' btrfs pool. I'll copy off the existing data, replace both 1tb ssd's with 2tb ssd's, format, name as 'cache_n', then move data back over.

 

9 hours ago, JorgeB said:

though you can do a full wipe on it to avoid that

by "it", I think you meant the other device (the 2tb ssd)? which should be easy enough

 

Cheers

  • Community Expert
9 hours ago, artkingjw said:

I think you meant the other device (the 2tb ssd)?

Yep, you can use for example

blkdiscard -f /dev/sdX

 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.