Re: unexpected XFS SB magic number

[Russell Cattelan <cattelan@thebarn.com>]

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On Fri, 2006-12-22 at 12:42 -0500, Gaspar Bakos wrote:
> Dear all,
> 
> I have a 12 x 500Gb RAID-5 hardware RAID array on an ARECA 1130-ML
> controller. There is one single partition on it, exported as /dev/sdc1.
> This configuration used to work fine for 4 months.
> Then the computer crashed a couple of times, and led to a situation where
> 
> xfs_check /dev/sdc1 output is:
> 
> xfs_check: unexpected XFS SB magic number 0x45464920
> xfs_check: size check failed
> xfs_check: read failed: Invalid argument
> xfs_check: data size check failed
> xfs_check: failed to alloc 58876353264 bytes: Cannot allocate memory

What does 
xfs_db /dev/sdc1
sb 0
p 

look like?
That will print out the contents of the superblock

> 
> I also checked the RAID, and seemingly the controller is fine; I can
> communicate with it, all 12 disks are visible, their SMART status is
> OK, the RAID-5 is reported to be in 'normal' condition, etc.
> 
> [root@localhost ~]# xfs_db -r /dev/sdc1
> xfs_db: unexpected XFS SB magic number 0x45464920
> xfs_db: size check failed
> xfs_db: read failed: Invalid argument
> xfs_db: data size check failed
> xfs_db: failed to alloc 58876353264 bytes: Cannot allocate memory
> 
> --------------------
> 
> [root@localhost ~]# xfs_repair -nv /dev/sdc1
> 
> Phase 1 - find and verify superblock...
> bad primary superblock - bad magic number !!!
> attempting to find secondary superblock...
> ................................................................................
> ...
> ....................found candidate secondary superblock...
> 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.
> 
> ----------------
> 
> 
> I would very much appreciate advice on how to proceed in such situation.
> I worry that xfs_repair will repair, but may leave a mess that is hard
> to recover. I am hoping there may be a safer way.
> 
> 
> Best regards
> Gaspar
> 
-- 
Russell Cattelan <cattelan@thebarn.com>

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