No Volumes No Shares - Superblock Issue?

[NigelBrownless]

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xfs_repair -n /dev/md4

Is running....It reported an issue with the Superblock, and is now trying to find a backup Superblock.
Currently just showing lots of "dots" on the Console, but it still looking.

Will keep you posted...

[NigelBrownless]

Final Output.....

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........................................................................................................
..................found candidate secondary superblock...
error reading superblock 17 -- seek to offset 2123235655680 failed
unable to verify superblock, continuing...
found candidate secondary superblock...
verified secondary superblock...
would write modified primary superblock
Primary superblock would have been modified.
Cannot proceed further in no_modify mode.
Exiting now.


[fvdw]

well it seems to be happy with one of the secondary superblocks so I would suggest run xfs_repair without the -n option and keep fingers crossed

[NigelBrownless]

OK....Will initiate that now, and feedback when complete.

[NigelBrownless]

Output as follows....

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.........found candidate secondary superblock...
error reading superblock 17 -- seek to offset 2123235655680 failed
unable to verify superblock, continuing...
found candidate secondary superblock...
verified secondary superblock...
writing modified primary superblock
sb realtime bitmap inode 18446744073709551615 (NULLFSINO) inconsistent with calculated value 129
resetting superblock realtime bitmap ino pointer to 129
sb realtime summary inode 18446744073709551615 (NULLFSINO) inconsistent with calculated value 130
resetting superblock realtime summary ino pointer to 130

fatal error -- couldn't allocate block map, size = 121968988


[fvdw]

pity not yet succes, it seems to set back to AG value to the wrong one and then we get same error as before.
Lets have a look what it has written to the primary superblock.

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dd if=/dev/md4 bs=1M count=1 of=primarySB-2.img

[fvdw]

If it is the same as the old one or contain some other changes the next steps will be writimg a new modified superblock to set AG size correct and then run xfs_repair with an option to use geometry as given in the primairy superblock

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xfs_repair -o force_geometry

To make a new primary superblock I need the current one (see previous post)

Furthermore we will write a few secondary superblock, just to be sure that as xfs_repair wants to verify the primairy superblock that it finds a secondary which is the same

[NigelBrownless]

Attached is the new Primary Superblock...

[fvdw]

Thre are some differences but some I don't trust to be correct and indeed AG size has been reset to the "wrong" value. Attached a new superblock with AG size and number updated as well as some bytes from SB-2 which I think are correct.
We will write this as primairy block and as backup block to next 2 AG's

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dd if=primairySB-new.img bs=1M count=1 of=/dev/md4
dd if=primairySB-new.img bs=1M count=1 seek=4096 of=/dev/md4
dd if=primairySB-new.img bs=1M count=1 seek=8192 of=/dev/md4

After that try xfs_repair as follow

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xfs_repair -o force_geometry /dev/md4

[NigelBrownless]

3 Superblocks written back. Output as expected....

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dd if=primarySB-new.img bs=1M count=1 of=/dev/md4
1+0 records in
1+0 records out
1048576 bytes (1.0MB) copied, 0.702953 seconds, 1.4MB/s
root@fvdw-sta-kirkwood:/ # dd if=primarySB-new.img bs=1M count=1 seek=4096 of=/dev/md4
1+0 records in
1+0 records out
1048576 bytes (1.0MB) copied, 0.176913 seconds, 5.7MB/s
root@fvdw-sta-kirkwood:/ # dd if=primarySB-new.img bs=1M count=1 seek=8192 of=/dev/md4
1+0 records in
1+0 records out
1048576 bytes (1.0MB) copied, 0.095892 seconds, 10.4MB/s