On Tue, Feb 03, 2009 at 11:47:37PM +0530, Kalpak Shah wrote: > On Tue, 2009-02-03 at 10:57 -0700, Nathan Dauchy wrote: > > 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? > > The "tar" package shipped with distros cannot recognize "lustre." > extended attributes and hence cannot be used for Lustre backups. > > You will need to use Lustre patched tar available for download at > http:// downloads.lustre.org/public/tools/lustre-tar/
I just did some testing with rsync-2.6.8-3.1 from rhel 5 and it appears to support Lustre's extended attributes with its -X (--xattrs) option. The test I ran was as follows: See if initial copy looks correct: - create some files in lustre (nonzero length) - stop lustre and remount mdt with -t ldiskfs on /mnt/lustre/mdt - create an ldiskfs file system on the MDS with -Oext_attr and mount on /mnt/lustre/mdt-backup - rsync -Xav --delete /mnt/lustre/mdt/ /mnt/lustre/mdt-backup - verify with getfattr -d -m '.*' -P that attrs are identical on all files in both copies Make sure rsync updates file/dir if only attrs change - unmount /mnt/lustre/mdt and restart lustre - run lfs setstripe --count -1 on an existing directory in lustre - stop lustre and remount mdt with -t ldiskfs on /mnt/lustre/mdt - verify with getfattr that attrs differ on that dir in both copies - repeat rsync - verify with getfattr that attrs are identical on that dir in both copies Verify that a restore works: - rm -rf /mnt/lustre/mdt/* - rsync -Xav --delete /mnt/lustre/mdt-backup/ /mnt/lustre/mdt - unmount /mnt/lustre/mdt and restart lustre - verify that md5sums of files created in first test match originals Jim _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
