On Sat, Dec 18, 2010 at 12:26:07PM +0100, Kevin Richter wrote: > Hi, > > I have an external USB 2TB harddisk with an XFS filesystem connected to > a Debian Lenny with a 2.6.33.4 kernel. > > 5 days ago I backuped my data to this external drive. While this backup > process the USB port got reset and now all the data on the xfs is lost. There's been garbage written all over this superblock: > The current XFS header bytes of the /dev/mapper/backup volume: > 00000000 58 46 53 42 00 00 10 00 00 00 00 00 1c d8 c3 a4 |XFSB.........Øä| > 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > 00000020 ec 24 29 ae 9c 2f 4a 75 a8 59 58 14 b5 2d 5e ac |ì$)®./Ju¨YX.µ-^¬| > 00000030 00 00 00 00 10 00 00 04 00 00 00 00 00 00 00 80 |................| Ok up to here (first 64 bytes) > 00000040 98 55 e4 53 ef e6 e9 03 9a 71 4f 19 3f 8b 6f 14 |.UäSïæé..qO.?.o.| > 00000050 75 d6 51 9a dd 84 53 3e c4 80 ae a1 c2 83 53 5e |uÖQ.Ý.S>Ä.®¡Â.S^| > 00000060 69 c3 f8 1b 35 0b 15 f2 4f 15 46 42 79 6f 8b 13 |iÃø.5..òO.FByo..| > 00000070 4c 65 64 ba 38 cd 51 8b 00 00 00 00 2c f9 ac 2c |Ledº8ÍQ.....,ù¬,| > 00000080 47 91 80 45 73 3e 93 77 8f 95 80 81 ab 8b b8 eb |G..Es>.w....«.¸ë| This is all garbage (second 64 bytes) > 00000090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| Might be ok. > 000000a0 ec 24 29 ae 9c 2f 4a 75 a8 59 58 14 b5 2d 5e ac |ì$)®./Ju¨YX.µ-^¬| Garbage > 000000b0 00 00 00 00 10 00 00 04 00 00 00 00 00 00 00 80 |................| Might be ok > 000000c0 98 55 e4 53 ef e6 e9 03 9a 71 4f 19 3f 8b 6f 14 |.UäSïæé..qO.?.o.| > 000000d0 75 d6 51 9a dd 84 53 3e c4 80 ae a1 c2 83 53 5e |uÖQ.Ý.S>Ä.®¡Â.S^| > 000000e0 69 c3 f8 1b 35 0b 15 f2 4f 15 46 42 79 6f 8b 13 |iÃø.5..òO.FByo..| > 000000f0 4c 65 64 ba 38 cd 51 8b 00 00 00 00 2c f9 ac 2c |Ledº8ÍQ.....,ù¬,| > 00000100 47 91 80 45 73 3e 93 77 8f 95 80 81 ab 8b b8 eb |G..Es>.w....«.¸ë| Garbage. > 00000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > 00000120 ec 24 29 ae 9c 2f 4a 75 a8 59 58 14 b5 2d 5e ac |ì$)®./Ju¨YX.µ-^¬| > 00000130 00 00 00 00 10 00 00 04 00 00 00 00 00 00 00 80 |................| > 00000140 98 55 e4 53 ef e6 e9 03 9a 71 4f 19 3f 8b 6f 14 |.UäSïæé..qO.?.o.| > 00000150 75 d6 51 9a dd 84 53 3e c4 80 ae a1 c2 83 53 5e |uÖQ.Ý.S>Ä.®¡Â.S^| > 00000160 69 c3 f8 1b 35 0b 15 f2 4f 15 46 42 79 6f 8b 13 |iÃø.5..òO.FByo..| > 00000170 4c 65 64 ba 38 cd 51 8b 00 00 00 00 2c f9 ac 2c |Ledº8ÍQ.....,ù¬,| > 00000180 47 91 80 45 73 3e 93 77 8f 95 80 81 ab 8b b8 eb |G..Es>.w....«.¸ë| > 00000190 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > 000001a0 ec 24 29 ae 9c 2f 4a 75 a8 59 58 14 b5 2d 5e ac |ì$)®./Ju¨YX.µ-^¬| > 000001b0 00 00 00 00 10 00 00 04 00 00 00 00 00 00 00 80 |................| > 000001c0 98 55 e4 53 ef e6 e9 03 9a 71 4f 19 3f 8b 6f 14 |.UäSïæé..qO.?.o.| > 000001d0 75 d6 51 9a dd 84 53 3e c4 80 ae a1 c2 83 53 5e |uÖQ.Ý.S>Ä.®¡Â.S^| > 000001e0 69 c3 f8 1b 35 0b 15 f2 4f 15 46 42 79 6f 8b 13 |iÃø.5..òO.FByo..| > 000001f0 4c 65 64 ba 38 cd 51 8b 00 00 00 00 2c f9 ac 2c |Ledº8ÍQ.....,ù¬,| These should all be zero. Basically, whatever happened to cause the USB reset has resulted in corruption of various sectors of the hard drive. If you can't get your usb drive to work reliably, then don't expect the filesystem to stay intact. I'd start by replacing the USB cable and probably the enclosure, writing a pattern to the entire harddrive (e.g. 0xa5a55a5a) and verifying you can read it back without corruption or USB resets. If you can't get your USB drive to work reliably, then it's not a good medium for storing backups.... If that is fine, mkfs the filesystem on it and redo your backup again. > It is a problem with the interaction of LUKS, XFS and USB? You are encrypting the external drive? That would explain the garbage then - a single bit error in a sector will render it completely incorrect.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
