Re: RAID5 won't mount after reducing disks from 8 to 6

[Joe Landman <joe.landman@gmail.com>]

On 02/16/2011 08:47 PM, Matt Tehonica wrote:
> To be honest, I couldn't find good directions on how exactly to
> resize an array to be smaller so I put some bits and pieces together
> to do it.  Guess I didn't understand everything beforehand because I
> didn't read anything about resizing the file system.  I thought
> setting the "array-size" would take care of moving data before
> rebuilding onto the 6 disks.
>
> Since I haven't resized the XFS filesystem, any recommendations on
> what to do next?  Think it's possible to recover any of the data?
> For what it's worth, I haven't done anything to the 2 disks that I
> was going to remove.

XFS isn't shrinkable.  See if

	xfs_check /dev/mdX

tells you anything.  If you have a backup, a restore would be the 
fastest option.  If you don't, and you have no other possible way of 
recovering the data from another source, try

	xfs_repair /dev/mdX

I usually run it with the verbose flag on so I can see what its doing.

I am not sure it will work, or result in recoverable data.

If you need to shrink xfs file systems, in general, it is best to use 
xfsdump/xfsrestore or tar.

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-- 
Joe Landman
landman@scalableinformatics.com