On 2010-02-04, at 11:23, Hervé Kergourlay wrote: > When I create a file on my lustre FS, add acl and a test xattr named > "attr1", with the standard tools "attr", there is 2 xattr > > santos.root(55) [dev->Bin] attr -l /mnt/mycltlustre/hky/bck/file.txt > Attribute "lov" has a 56 byte value for /mnt/mycltlustre/hky/bck/ > file.txt > Attribute "attr1" has a 4 byte value for /mnt/mycltlustre/hky/bck/ > file.txt > > with an own developped tools, there is I can see 2 lustre xattr, > trusted.lov and lustre.lov
The lustre.lov and trusted.lov attributes are really the same thing internally. We used to use only trusted.lov, but it is not possible for non-root users to read/write this attribute. > I see some informations on backup where extended attributes are > supposed to be backuped and restored > > https://bugzilla.lustre.org/show_bug.cgi?id=5716 or in the lustre - > operation manual (chapter 15) > > But I would like to get more informations about theses two extended > attributes. Which role they have (store lustre splitting > information, I could imagine), do we need really to backup them ? > and restore them ? > They should be recreated as restoring a file, it's recreating a > file ?? It isn't _required_ to backup and restore these attributes if you are just creating a tar archive from the mounted lustre filesystem. If they are not specified then the MDS will supply default attributes for the file/directory. If the lustre.lov and/or trusted.lov attributes are backed up/restored (as can be done with the patched tar available at downloads.lustre.org) then all files will keep the same stripe count and stripe size. > Or perhaps it's linked with the MDS backup, in case of full > desaster / recovery. If you are doing a MDT-filesystem backup on an ldiskfs-type mount of the MDT, then it is critical to back up the trusted.lov attributes, or your filesystem will contain no data in it when it is restored. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
