On Aug 19, 2008 20:27 -0400, Mag Gam wrote: > Yes, I have looked thru the lists but I could not really get this > question answered. tune2fs is a ext2/3 setting, and I though each file > I create on a Lustre filesystem an inode gets created on the MDS and > the OST as an object. > > But, I don't understand how there is that much of a space discrepancy.
The reason for this discrepancy is because of "safety". It is possible that the striping is too large to fit into the inode, so it needs an external block. If that is needed for every remaining inode on the MDS then the limit on the number of files created is equal to the number of free blocks on the MDS. In order to avoid over-stating the number of possible files that can be created (sometimes important to e.g. RPM or regression tests), "df" and "lfs df" will return min(free inodes, free blocks) for the inode count. If (as usually happens) inodes are created that do not need external blocks to store the striping information then more inodes "appear" (i.e. as "IUsed" increases so does "Inodes" and "IFree" stays constant). > Also, how does striping account for in inodes? Lets say I stipe a file > on 4 OSTs, I suppose 5 (1 for MDS, 4 for OSTs) inodes are occupied, > correct? Yes, though each of the inodes are in different filesystems. > On Tue, Aug 19, 2008 at 4:30 PM, Brian J. Murrell <[EMAIL PROTECTED]> wrote: > > On Sun, 2008-08-17 at 15:50 -0700, Mag Gam wrote: > >> My departments Lustre's lfs df -i looks like this > >> > >> UUID Inodes IUsed IFree IUse% Mounted on > >> xfs001-MDT0000_UUID 82565322 19073586 63491736 23% > >> /xfs/engine1/xfs001[MDT:0] > >> xfs001-OST0000_UUID 41943040 5076445 36866595 12% > >> /xfs/engine1/xfs001[OST:0] > >> xfs001-OST0001_UUID 41943040 3735715 38207325 8% > >> /xfs/engine1/xfs001[OST:1] > >> xfs001-OST0002_UUID 41943040 4784447 37158593 11% > >> /xfs/engine1/xfs001[OST:2] > >> xfs001-OST0003_UUID 41943040 4556627 37386413 10% > >> /xfs/engine1/xfs001[OST:3] > >> > >> filesystem summary: 82565322 19073586 63491736 23% > >> /xfs/engine1/xfs001 > >> > >> > >> Is it safe to say, " > >> My MDT has "19073586" 19 million inodes free? or should I consider. > >> > >> However, when I check my inode count on my mds using tune2fs it reports > >> this. > >> Inode count: 524288000 > >> Free inodes: 505214414 > >> > >> Am I missing something? > > > > Yes. lfs df does not simply report the free inodes on the MDT. It's > > more complicated than that. This has been discussed either here or in a > > bugzilla bug (don't recall which). I don't recall the bug or when the > > lustre-discussion was, offhand, but a search should not be terribly > > difficult to find the answer. > > > > b. > > > > > > _______________________________________________ > > Lustre-discuss mailing list > > [email protected] > > http://lists.lustre.org/mailman/listinfo/lustre-discuss > > > > > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss 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
