[Lustre-discuss] MDT backup

[Nathan Dauchy]

Brian J. Murrell wrote:
> On Mon, 2009-01-19 at 22:46 -0600, Alex Kulyavtsev wrote:
>> Hi,
>> what is the right way to backup MDT ?
> 
> I think this is covered in the operations manual.
> 

The manual does indeed cover backups:
http://manual.lustre.org/manual/LustreManual16_HTML/BackupAndRestore.html

It includes this step:

>  3. Back up the EAs, run:
> getfattr -R -d -m '.*' -P . > ea.bak
> 

Is that necessary for newer versions of tar that support the "-xattrs"
option?  From the man page (I have GNU tar 1.15.1):

--xattrs	this  option  causes  tar  to  store  each  file's
		extended  attributes in the archive. This option also
		enables --acls and--selinux if they haven't been
		set already, due to the fact that the data for those
		are stored in special xattrs.

Also, AFAIK, cpio will archive extended attributes as well.

Is either 'tar --xattrs' or 'cpio' sufficient for capturing all the
Lustre MDT information?  Would that eliminate the need for the
'getfattr' step, and cut the time for backup almost in half by requiring
only one pass through the filesystem?

Thanks,
Nathan