PHYSICAL VOLUME ERRORS

[oprakash]

Hi,

I want to check the errors in physical volume in hp ux 11.00, can you suggest me few commands. Hope FSCK will help me but i dont know the usage of this command.

[TTr]

The fsck command is for fixing filesystems, it may or may not find physical disk errors. A better way to check for physical disk errors it to read the entire disk device using the dd command.
dd if=/dev/rdsk/cXtYdZ of=/dev/null bs=1024k
Check out the man pages for the dd command
If you use LVM you can also read the logical volumes that may be sitting on the top of the dsk device as in
dd if=/dev/vgNN/lvolX of=/dev/null bs=1024k
Most disk errors will translate into logical volume errors with stale extends, mirrors and volumes.

[Suraj K Sankari · Accepted solution]

There are 3 ways to check the physical disk
1.ioscan
2.diskinfo
3.dd

If ioscan output is having any "UNCLAIMED UNKNOWN" that means disk is missing or UNCLAIMED kernel not able to detucted or multipal path problem

If ioscan output is showing no UNCLAIMED then you can used "diskinof" command here you need to check the size if output is showing 0 zero that means device is not ready or fualty.

If both is ioscan and diskinfo succeed then we need to try with dd command and no I/O errors should be reported.

successful read of the first 64 megabytes of the disk

# dd if=/dev/rdsk/c0t5d0 of=/dev/null bs=1024k count=64
64+0 records in
64+0 records out

unsuccessful read of the whole disk will be 0 records in 0 records out
# dd if=/dev/rdsk/c1t3d0 of=/dev/null bs=1024k
dd read error: I/O error
0+0 records in 0+0 records out

Suraj

[Vivek Bhatia]

Hi,

As rightly said by Suraj you can you the below commands to diagnose that the disk.

1.ioscan
2.diskinfo
3.dd

http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad_WP.pdf

Regards,
Vivek

[oprakash]

Hi,

Thanks a lot suraj, I checked for disk I/O errors.