file system damage

[Quegwer]

Hello Admins,

i have to deal with a damaged file-system on a 10.20-box.
It resides on a raid-system , all the other file systems of the raid seem ok.

> fsck -F vxfs -o full /dev/rs2/rs35

log replay in progress
vxfs fsck: file system does not contain a valid log
vxfs fsck: cannot perform log replay
pass0 - checking structural files
pass1 - checking inode sanity and blocks
vxfs fsck: fsck read failure bno = -1946760533, off = 0, len = 8192

It seems that the directory-mapping has crashed:

> vxdump -f - /dev/rs2/rs35 | vxrestore -r -f -

vxdump: Date of this level 0 dump: Thu Dec 18 12:04:47 2003
vxdump: Date of last level 0 dump: the epoch
vxdump: Dumping /dev/rs2/rrs35 (/rs2/rs35) to standard output
vxdump: mapping (Pass I) [regular files]
vxdump: mapping (Pass II) [directories]
vxdump: estimated 48333826 blocks (23600.50MB).
vxdump: dumping (Pass III) [directories]
vxdump: inode bmap failure inode 49720 offset 0
vxdump: inode bmap failure inode 49727 offset 0
vxdump: Broken pipe
vxdump: The ENTIRE dump is aborted.

Still i can get the inodes of the files i am missing ( using ff )
and according to fsdb the data seem to be all right.

Does anyone know how to extract the data by given inode-
number from that filesystem?

Thank you in advance

Martin

[James Murtagh · Accepted solution]

Hi Martin,

This is not an easy procedure, especially if there are indirect blocks. However, I have attached a document showing a way to do it.....you need to use fsdb to find the block mapping then use dd to copy those blocks out to a regular file. I hope it helps, any questions let me know.

Cheers,

James.

[Quegwer]

Hello James,

thanks a lot, it worked well; I was able to pick some files from the disk which i already got from a backup, but
switching to some of the newer data, the filesystem seems to
be to badly damaged. All i can get is

> 50135 i
read failed at block 3918453 error = 6

but again, thanks for your answer

Martin

[M. Ismail]

Hello James,

Thanks a lot!
The trick to extract the files from an unmounted(or damaged) filesystem is excellent.

This shows your high level of expertise in the field of HP-UX.

Thanks & Regards,
Ismail.