currently, i can see these two options for recovering the data:
1) send the disk 3 (the broken one) for repair, copy the data, and
restore the array using disks 2-5
this brings more expenses for the client but the chances for
recovering the data are probably pretty high, if the data from the disk
3 is recovered - i might need to use --force on the assembly or even
--assume-clean as the number of events is little bit increased because i
re-assembled the array from disks 2-6 after i made the backups of the
other disks
2) investigate deeper whether i can or cannot re-create the array using
disks 1, 2, 4 and 5
i am confused about this solution, because of that (imo) interrupted
rebuild on disk 1 (Recovery Offset : 4910216 sectors). on the other
hand, i was able to assemble the array, read the lvm logical volume,
"just" the btrfs filesystem was reported to be seriously corrupted that
even btrfs recovery recovered nothing. but i didn't try to repair the
filesystem yet.
any hints?
Dne 2024-08-22 17:02, Miroslav Šulc napsal:
hello,
a broken synology raid5 ended up on my desk. the raid was broken for
quite some time, but i got it from the client just a few days back.
the raid consisted of 5 disks (no spares, all used):
disk 1 (sdca): according to my understanding, it was removed from the
raid, then re-added, but the synchronization was interrupted, so it
cannot be used to restore the raid
disk 2 (sdcb): is ok and up to date
disk 3 (sdcc): seems to be up to date, still spinning, but there are
many issues with bad sectors
disk 4 (sdcd): is ok and up to date
disk 5 (sdce): is ok and up to date
the raid ran in degraded mode for over two months, client trying to
make a copy of the data from it.
i made copies of the disk images from disks 1, 2, 4, and 5, at the
state shown below. i didn't attempt to make a copy of disk 3 so far.
since then i re-assembled the raid from disk 2-5 so the number of
events on the disk 3 is now a bit higher then on the copies of the disk
images.
according to my understanding, as the disk 1 never finished the sync, i
cannot use it to recover the data, so the only way to recover the data
is to assemble the raid in degraded mode using disk 2-5, if i ever
succeed to make a copy of the disk 3. i'd just like to verify that my
understanding is correct and there is no other way to attempt to
recover the data. of course any hints are welcome.
here is the info from the partitions of the raid:
/dev/sdca5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x2
Array UUID : f697911c:bc85b162:13eaba4e:d1152a4f
Name : DS_KLIENT:4
Creation Time : Tue Mar 31 11:40:19 2020
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 15618390912 (7447.43 GiB 7996.62 GB)
Array Size : 31236781824 (29789.72 GiB 31986.46 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Recovery Offset : 4910216 sectors
Unused Space : before=1968 sectors, after=0 sectors
State : clean
Device UUID : 681c6c33:49df0163:bb4271d4:26c0c76d
Update Time : Tue Jun 4 18:35:54 2024
Checksum : cf45a6c1 - correct
Events : 60223
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 0
Array State : AAAAA ('A' == active, '.' == missing, 'R' ==
replacing)
/dev/sdcb5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : f697911c:bc85b162:13eaba4e:d1152a4f
Name : DS_KLIENT:4
Creation Time : Tue Mar 31 11:40:19 2020
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 15618390912 (7447.43 GiB 7996.62 GB)
Array Size : 31236781824 (29789.72 GiB 31986.46 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=0 sectors
State : clean
Device UUID : 0f23d7cd:b93301a9:5289553e:286ab6f0
Update Time : Wed Aug 14 15:09:24 2024
Checksum : 9c93703e - correct
Events : 60286
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 1
Array State : .AAAA ('A' == active, '.' == missing, 'R' ==
replacing)
/dev/sdcc5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : f697911c:bc85b162:13eaba4e:d1152a4f
Name : DS_KLIENT:4
Creation Time : Tue Mar 31 11:40:19 2020
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 15618390912 (7447.43 GiB 7996.62 GB)
Array Size : 31236781824 (29789.72 GiB 31986.46 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=0 sectors
State : clean
Device UUID : 1d1c04b4:24dabd8d:235afb7d:1494b8eb
Update Time : Wed Aug 14 12:42:26 2024
Checksum : a224ec08 - correct
Events : 60283
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 2
Array State : .AAAA ('A' == active, '.' == missing, 'R' ==
replacing)
/dev/sdcd5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : f697911c:bc85b162:13eaba4e:d1152a4f
Name : DS_KLIENT:4
Creation Time : Tue Mar 31 11:40:19 2020
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 15618390912 (7447.43 GiB 7996.62 GB)
Array Size : 31236781824 (29789.72 GiB 31986.46 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=0 sectors
State : clean
Device UUID : 76698d3f:e9c5a397:05ef7553:9fd0af16
Update Time : Wed Aug 14 15:09:24 2024
Checksum : 38061500 - correct
Events : 60286
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 4
Array State : .AAAA ('A' == active, '.' == missing, 'R' ==
replacing)
/dev/sdce5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : f697911c:bc85b162:13eaba4e:d1152a4f
Name : DS_KLIENT:4
Creation Time : Tue Mar 31 11:40:19 2020
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 15618390912 (7447.43 GiB 7996.62 GB)
Array Size : 31236781824 (29789.72 GiB 31986.46 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=0 sectors
State : clean
Device UUID : 9c7077f8:3120195a:1af11955:6bcebd99
Update Time : Wed Aug 14 15:09:24 2024
Checksum : 38177651 - correct
Events : 60286
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 3
Array State : .AAAA ('A' == active, '.' == missing, 'R' ==
replacing)
thank you for your help.
miroslav
