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Topics: PowerHA / HACMP, SAN, SDD, Storage

Reservation bit

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

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