disk read error

[dave broome_2]

on re-boot on of our disks failed to mount. On performing a fsck we get the following message ...
# fsck -y -ofull /dev/vg01/lvol1
vxfs fsck: file system had I/O error(s) on meta-data.
log replay in progress
pass0 - checking structural files
pass1 - checking inode sanity and blocks
pass2 - checking directory linkage
pass3 - checking reference counts
pass4 - checking resource maps
vxfs fsck: fsck read failure bno = 1440, off = 0, len = 8192
file system check failure, aborting ...

One of our database files is on this disk, does anyone have any ideas on what we can do to retrieve it?

Thanks,

Dave

[Pete Randall]

Dave,

I would use dd to check the disk:

"dd if=/dev/rdsk/cNtNdN of=/dev/null bs=1024k"

If you get any errors from dd, you've got a bad disk and you need to replace it. Hopefully you've got a backup.


Pete

[dave broome_2]

not sure I did this right but this is what I got ..
# dd if=/dev/vg01/ of=/dev/null bs=1024k
0+1 records in
0+1 records out

[Stefan Farrelly]

This error implies your filesystem on this disk has an unrecoverable error. You will have to newfs it and reload your data. Ive had these errors before and despite lots of effort cant recover from them. This sort of error is usually caused by a bad block developing on the physical disk, and some of your data on it is thus lost.

Because your disk has developed a bad block doesnt mean it needs replacement - yet.

[Stefan Farrelly]

your dd command only read the vg header, you want to do;

dd if=/dev/vg01/rlvol1 of=/dev/null bs=1024k

[dave broome_2]

thanks for your comments, we don't have a backup (for one reason or another) and could really do with recovering the data. Is there anyway that I can try?

[dave broome_2]

here's the proper output ...
# dd if=/dev/vg01/rlvol1 of=/dev/null bs=1024k
dd read error: I/O error
1+0 records in
1+0 records out
#

[Pete Randall]

Dave,

The first step is to prove that the disk is OK. That's what the dd command is for (use Stefan's /dev/vg01/rlvol1 recommendation). If the disk is OK, your only real chance of correcting a bad block is through fsck. You can try fsck again, but I think it's unlikely to be successful.


Pete

[Pete Randall]

Dave,

That dd output says "bad disk" to me.


Pete

[Stefan Farrelly]

sorry, the dd error indicates your filesystem is gone. I doubt very much you will be able to recover anything. Sorry.

[dave broome_2]

ok, thanks for your help.