lto/xfs filesystem recover.

[Chris Murphy]

On Oct 29, 2014, at 10:03 AM, Gary Artim <gartim at gmail.com> wrote:

> I have a xfs filesystem (4 drives) and one died /dev/sdc1. It was used for backup and trying to recover one directory. Any ideas would be great. I was able to drop the volume that died and have a pv of 3 now, but getting lvm to recognize (create a dev) is not happening
> 
> parted /dev/sdx
> mklabel gpt
> mkpart primary xfs 1 -1 (sometime xfs doesnt work until the xfsprogs are installed and reboot)
> set 1 lvm on
> 
> do this for each drive.
> pvcreate /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
> vgcreate backup /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
> lvcreate -L 9T -n backuplv backup
> mkfs.xfs -L backuplv /dev/mapper/backup-backuplv
> /dev/mapper/backup-backuplv /xfs xfs   (in fstab)

I can't tell how the four drives were arranged such that there's one XFS volume. Is this LVM linear (default)? If so I'd say it's toast, but whether you can maybe mount it ro and use the remaining metadata in each AG to extract data on each drive is probably best asked on the XFS list. The same applies to md linear/concat. If it's raid0 then it's definitely toast.

I'll assume it's not raid1/mirror or you'd be able to use it degraded and recovery is pretty sraightforward.

Chris Murphy