On Fri, 2009-08-21 at 11:30 +1000, Yaroslav Tykhiy wrote: > Hi there, > > On 19/08/2009, at 8:38 PM, Craig Ringer wrote: > > You should also `chkdsk' your file system(s) and use a SMART > > diagnostic tool to test your hard disk (assuming it's a single ATA > > disk). > > By the way, `chkdsk' in Windows or `fsck' in Unix can, in a way, be a > _source_ of file loss if the file metadata got damaged badly, e.g., by > a system crash, and the file node has to be cleared. So I've always > been curious if there is a way to retrieve surviving records from a > PostgreSQL database damaged by file loss. Good point and good question. One thing that'd _REALLY_ help recover PostgreSQL databases would be if files defining the tables had a header containing: - A magic number or string - The PostgreSQL version - The file path/name relative to the pg data root eg: PGSQL84\x00base/11511/2699 That'd be a big bonus if they turned up in lost+found, and would also assist in recovery of a database from a file system with completely destroyed or unusable metadata (eg: dead superblocks). Then again, with the DB files not having end markers and with the potential for file fragmentation you're probably not going to recover a DB from a completely mangled FS anyway. Help identifying DB files from lost+found would be very nice, though. Of course, we all keep good backups so nobody'll ever _need_ this sort of thing, right? Right? *sigh* -- Craig Ringer -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
