[NBLUG/talk] mount and fsck errors

[Ron Wickersham]

On Sun, 16 May 2004, micxz wrote:

> I'm trying to help my friend in debugging some file system errors he
> started getting after the power went out!
---snip---
> /dev/sdb2 and /dev/sda1 are SCSI and /dev/hda1 is IDE. The issue lie
> within the IDE drive or hda1.
---snip---
> I've read, "In a particularly bad case you can try mke2fs -S (make
> superblocks and group descriptors only). This is described in the man
> page --- and is for "last ditch" efforts only." But I'm afraid to try
> this as there is data we would love to have on there. Any suggestions
> would be great as I have very little experience with disk errors.

hi Micxz,

1) when recovering stuff you have to make decisions that are undoable so
   you risk loosing data.  what i do is dd a copy of the entire disk to
   a spare drive and do my recovery work on the copy.  that way the
   original is available even if recovery appears to go well...sometimes
   it's a week or two until you discover that not everything is really ok.

2) i'm not familiar with the recovery of the file system type you have
   here, but on regular unix file systems there are lots of copies of
   the superblocks so if one is munged you can use one of the good ones.
   look for mounting the file system with an alternate superblock.  in
   standard filesystems there is a command to go thru the process of
   new superblocks but just report the list of locations they would go
   without actually writing them to the drive.

good luck.

-ron

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