Dear Andreas, Thanks so much for your valuable suggestion. Using the
ll_recover_lost_found_objs [-hv] -d lost+found_directory command I have recovered most of the lost files from "lost+found". I am very appreciate your kindly help. Best Regards, T.H.Hsieh On Fri, Mar 13, 2009 at 06:23:04AM -0600, Andreas Dilger wrote: > On Mar 13, 2009 11:03 +0800, thhsieh wrote: > > There is another tip I can share here. After following Andreas's > > suggestions, we finally got back all the OSTs. But still there > > are a lot of files cannot be recovered. If you use "ls -l" command, > > you can very easily to identify such kind of files: > > > > -rw-r--r-- 1 thhsieh thhsieh 61440008 2007-05-21 18:49 EIV27 > > -rw-r--r-- 1 thhsieh thhsieh 61440008 2007-05-21 18:49 EIV28 > > ?--------- ? ? ? ? ? EIV29 > > -rw-r--r-- 1 thhsieh thhsieh 61440008 2007-05-21 18:49 EIV30 > > -rw-r--r-- 1 thhsieh thhsieh 19488 2008-09-18 16:04 fort.8 > > > > where "EIV29" is the corrupted file. > > Right, because "ls -l" got an error when reading the size for > this file. > > > Then in /mnt/lost+found/, you may see a lot of losted files there. > > But still difficult to identify which one is which. > > > > If we can know the features of the original file, e.g., its creating or > > last modifying time, its roughly size, its owner, or its type, then its > > is still possible to pick up the correct one. For example, yesterday > > I tried to correctly pick up the "Zip archived" file from thousands of > > files, by picking out the files belong to the owner, and use the > > > > file <filename> > > > > to check its original format. Very fortunately there is only one "Zip" > > format file, so that is it. > > > > Since this technique is very tedious, but still cannot guarantee to > > recover files, it is only useful to recover a few files which may be > > the most critical. However, if you do have very important file which > > can not be losted, then this way may be worth to try. > > There is a tool specifically for this, which I mentioned in my earlier > email "ll_recover_lost_found_objs", which will run against the ldiskfs > mounted filesystem: > > Usage: ./lustre/utils/ll_recover_lost_found_objs [-hv] -d lost+found_directory > You need to mount the corrupted OST filesystem andprovide the path for the > lost+found directory as the -d option, for example: > ll_recover_lost_found_objs -d /mnt/ost/lost+found > > > This will move all (or at least most) of the objects from lost+found > back to their place in the O/0/d* directories, and you will have most > of your files back. > > > The first time Lustre writes to an object it saves the MDS inode number > and the objid as an extended attribute on the object, so that in the > case of a directory corruption on the OST it is possible to recover, > as you need to do. > > 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
