If you wish to get rid of the SCSI disk reservation bit on SCSI, SSA and VPATH devices, there are two ways of achieving this:

Firstly, HACMP comes along with some binaries that do this job:

# /usr/es/sbin/cluster/utilities/cl_SCSIdiskreset /dev/vpathx

Secondly, there is a little (not official) IBM binary tool called "lquerypr". This command is part of the SDD driver fileset. It can also release the persistant reservation bit and clear all reservations:

First check if you have any reservations on the vpath:

# lquerypr -vh /dev/vpathx

Clear it as follows:

# lquerypr -ch /dev/vpathx

In case this doesn't work, try the following sequence of commands:

# lquerypr -ch /dev/vpathx
# lquerypr -rh /dev/vpathx
# lquerypr -ph /dev/vpathx

If you'd like to see more information about lquerypr, simply run lquerypr without any options, and it will display extensive usage information.

For SDD, you should be able to use the following command to clear the persistant reservation:

# lquerypr -V -v -c /dev/vpathXX

For SDDPCM, use:

# pcmquerypr -V -v -c /dev/hdiskXX

If you found this useful, here's more on the same topic(s) in our blog:

• EMC and MPIO
• Using mkvgdata and restvg in DR situations
• Creating a dummy disk device
• EMC and MPIO
• QHA