On Fri, 2007-11-02 at 18:55 +0100, Schlett, Matthias wrote: > We have an old GFS 5.2.1 cluster which is running without problems since 2004. > Unfortunally during a RAID-5 rebuild one of our filesystems was corrupted and cannot be mounted. > We also tried to check it by gfs_fsck, but it cannot find the superblock. > With the help of dd I dumped the first blocks of the device and compared it with a working filesystem. > It seems that the filesystem information is only moved an not destroyed. > > So my questions is, how can I restore the superblock and maybe restore the whole filesystem ? > > > m.schlett Hi Matthias, I would suggest extreme caution here. It depends on what exactly is wrong. If it's just the superblock, that's one thing, but if the superblock is relocated, chances are, so are lots of things, like the rgindex and the bitmaps telling which blocks are used. The preferred method, I would think, is to restore from backup after doing mkfs. If you don't have a backup and really need to get the information back, I would first use the gfs_edit util to examine what's really out there and how sane it is. Actually, if possible, I'd use gfs2_edit because it has a lot more features than gfs_edit and can operate, for the most part, on gfs1 file systems as well as gfs2. Of course, gfs2_edit only exists on newer releases. Also, on older systems, I don't think gfs2_edit was part of the cluster packages so you would have to build it from source code. If the superblock is bad, gfs_edit and/or gfs2_edit may not be able to read the file system either. You may not want to overwrite what's at the superblock's location, because it may be some other vital piece that should be relocated somewhere else. In short, the situation is not good. You really shouldn't mess with it unless you're intimately familiar with how a gfs file system looks on disk. Regards, Bob Peterson Red Hat Cluster Suite -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
