Lustre discuss - May 2011 - Lustre 1.8.4 - Local mount of ost for backup purposes, fs type ldiskfs or ext4?

Greetings,

I am doing a local mount of a >8TB ost device in a Lustre 1.8.4 
installation. The ost was built with a backfstype of ldiskfs.

When attempting the local mount:

     mount -t ldiskfs /dev/sdc /mnt/save/ost

I get:

     mount: wrong fs type, bad option, bad superblock on /dev/sdt,
                 missing codepage or other error

I am able to mount the same block device as ext4, just not as ldiskfs. I 
need to be able to mount as ldiskfs to get access to the extended 
attributes and back them up. Is this still the case with the ext4 
extensions for Lustre 1.8.4? I am able to mount read-only as ext4 but 
any attempt at reading the extended attributes with getfattr fails.

Thanks,

--Jeff

-- 
------------------------------
Jeff Johnson
Manager
Aeon Computing

jeff.johnson at aeoncomputing.com
www.aeoncomputing.com
t: 858-412-3810 x101   f: 858-412-3845
m: 619-204-9061

4905 Morena Boulevard, Suite 1313 - San Diego, CA 92117

Hi.

You didn''t say what your kernel version was.  Check dmesg,
you''ll likely
get a better reason for the failure there.  It''s possible that the
force_over_8tb option is needed and not passed along appropriately.
Check out Lustre bugzilla 24432 and attachment 32731 which honors the
force_over_8tb mount option.  It''ll be included in 1.8.6.

-Cory


On 05/11/2011 05:23 PM, Jeff Johnson wrote:
> Greetings,
> 
> I am doing a local mount of a >8TB ost device in a Lustre 1.8.4 
> installation. The ost was built with a backfstype of ldiskfs.
> 
> When attempting the local mount:
> 
>      mount -t ldiskfs /dev/sdc /mnt/save/ost
> 
> I get:
> 
>      mount: wrong fs type, bad option, bad superblock on /dev/sdt,
>                  missing codepage or other error
> 
> I am able to mount the same block device as ext4, just not as ldiskfs. I 
> need to be able to mount as ldiskfs to get access to the extended 
> attributes and back them up. Is this still the case with the ext4 
> extensions for Lustre 1.8.4? I am able to mount read-only as ext4 but 
> any attempt at reading the extended attributes with getfattr fails.
> 
> Thanks,
> 
> --Jeff
>

Well, that''s the opposite problem of Bug 24398.

Are you sure you are using the ext4-based ldiskfs?

Kevin


On May 11, 2011, at 4:23 PM, Jeff Johnson <jeff.johnson at aeoncomputing.com 
 > wrote:
> Greetings,
>
> I am doing a local mount of a >8TB ost device in a Lustre 1.8.4
> installation. The ost was built with a backfstype of ldiskfs.
>
> When attempting the local mount:
>
>    mount -t ldiskfs /dev/sdc /mnt/save/ost
>
> I get:
>
>    mount: wrong fs type, bad option, bad superblock on /dev/sdt,
>                missing codepage or other error
>
> I am able to mount the same block device as ext4, just not as  
> ldiskfs. I
> need to be able to mount as ldiskfs to get access to the extended
> attributes and back them up. Is this still the case with the ext4
> extensions for Lustre 1.8.4? I am able to mount read-only as ext4 but
> any attempt at reading the extended attributes with getfattr fails.
>
> Thanks,
>
> --Jeff
>
> -- 
> ------------------------------
> Jeff Johnson
> Manager
> Aeon Computing
>
> jeff.johnson at aeoncomputing.com
> www.aeoncomputing.com
> t: 858-412-3810 x101   f: 858-412-3845
> m: 619-204-9061
>
> 4905 Morena Boulevard, Suite 1313 - San Diego, CA 92117
>
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