Recover data from old cache drive?

[hermy65]

I lost a few files that were on my cache drive and was hoping to recover them from some older drives that used to be my cache drives but when i try to mount them in Unassigned Devices i get the following. Is there any possible way for me to recover the files i need or am i out of luck?

 

May 21 09:03:38 RackServ kernel: BTRFS info (device sdn1): disk space caching is enabled
May 21 09:03:38 RackServ kernel: BTRFS info (device sdn1): has skinny extents
May 21 09:03:38 RackServ kernel: BTRFS error (device sdn1): devid 5 uuid 9203c653-08ef-4d3a-8068-fb91544bafcb is missing
May 21 09:03:38 RackServ kernel: BTRFS error (device sdn1): failed to read the system array: -2
May 21 09:03:38 RackServ kernel: BTRFS error (device sdn1): open_ctree failed
May 21 09:03:38 RackServ unassigned.devices: Mount of '/dev/sdn1' failed. Error message: mount: /mnt/disks/Samsung_SSD_850_EVO_500G: wrong fs type, bad option, bad superblock on /dev/sdn1, missing codepage or helper program, or other error.
May 21 09:03:38 RackServ unassigned.devices: Partition 'Samsung SSD_850_EVO_500G' could not be mounted.

 

[JorgeB]

4 minutes ago, hermy65 said:

devid 5 uuid 9203c653-08ef-4d3a-8068-fb91544bafcb is missing

It will mount if all pool members are connected to the server (unless thee are other issues), and you just need to mount one of them, the others will be mounted together if found.

 

If you don't have the missing member it might mount in degraded mode if the pool was redundant, see here for command.

[hermy65]

53 minutes ago, johnnie.black said:

It will mount if all pool members are connected to the server (unless thee are other issues), and you just need to mount one of them, the others will be mounted together if found.

 

If you don't have the missing member it might mount in degraded mode if the pool was redundant, see here for command.

@johnnie.black I was able to find a potential 2nd drive that was part of it but was unable to get either to work using some of the commands from your link. Any other thoughts by chance?

 

root@RackServ:~# mount -o degraded,usebackuproot,ro /dev/sdn1 /x
mount: /x: wrong fs type, bad option, bad superblock on /dev/sdn1, missing codepage or helper program, or other error.
root@RackServ:~# mount -o ro,notreelog,nologreplay,degraded /dev/sdn1 /x
mount: /x: wrong fs type, bad option, bad superblock on /dev/sdn1, missing codepage or helper program, or other error.

root@RackServ:~# mount -o degraded,usebackuproot,ro /dev/sdo1 /x
mount: /x: wrong fs type, bad option, bad superblock on /dev/sdo1, missing codepage or helper program, or other error.
root@RackServ:~# mount -o ro,notreelog,nologreplay,degraded /dev/sdo1 /x
mount: /x: wrong fs type, bad option, bad superblock on /dev/sdo1, missing codepage or helper program, or other error.

root@RackServ:/mnt/disk4# btrfs restore -v /dev/sdn1 /mnt/disk4/mike
warning, device 5 is missing
warning, device 1 is missing
bad tree block 2115388817408, bytenr mismatch, want=2115388817408, have=0
ERROR: cannot read chunk root
Could not open root, trying backup super
warning, device 5 is missing
warning, device 1 is missing
bad tree block 2115388817408, bytenr mismatch, want=2115388817408, have=0
ERROR: cannot read chunk root
Could not open root, trying backup super
warning, device 5 is missing
warning, device 1 is missing
bad tree block 2115388817408, bytenr mismatch, want=2115388817408, have=0
ERROR: cannot read chunk root
Could not open root, trying backup super

root@RackServ:/mnt/disk4# btrfs restore -v /dev/sdo1 /mnt/disk4/mike
warning, device 1 is missing
bad tree block 1754592444416, bytenr mismatch, want=1754592444416, have=0
Couldn't read tree root
Could not open root, trying backup super
warning, device 1 is missing
bad tree block 1754592444416, bytenr mismatch, want=1754592444416, have=0
Couldn't read tree root
Could not open root, trying backup super
warning, device 1 is missing
bad tree block 1754592444416, bytenr mismatch, want=1754592444416, have=0
Couldn't read tree root
Could not open root, trying backup super

 

 

[JorgeB]

Sorry, I wasn't very clear, I meant to say use just the degraded option, with or without ro (readonly), but without usebackuproot:

 

mount -o degraded,ro

 

But looks like it's missing more than a device, and that might not be the only problem, if degraded won't work can't help more, you can try #btrfs on freenode irc, they are very helpful there, but pool might be beyond saving.