Changing physical disk storage of GPFS file systems

Answer

To change the underlying physical disks used for GPFS file system data storage, perform the following steps:

1. Add the new disks to the GPFS file system until the file system is doubled in size by issuing the following command as root for each disk:
   db2cluster -cfs -add -filesystem <fs-name> -disk <disk-path>
   
   Note: The above command should be run sequentially for each disk.
   
2. Repeat the first step on each file system.
   
3. If a GPFS disk tiebreaker is in use, update the disk used by following these instructions:
   
   a. Stop all applications
   b. db2stop
   c. db2stop instance on <host> (on all hosts)
   d. db2cluster -cm -enter -maintenance -all
   e. db2cluster -cfs -enter -maintenance -all
   f. db2cluster -cfs -set -tiebreaker -majority
   g. db2cluster -cfs -set -tiebreaker -disk <disk-path>
   h. db2cluster -cm -exit -maintenance -all
   i. db2cluster -cfs -exit -maintenance -all
   j. db2start
   k. Restart applications
   
4. If a TSA disk tiebreaker is in use, update the disk by issuing the following command as root:
   db2cluster -cm -set -tiebreaker -disk <disk-path>
   
5. Remove the old disks from the file system by issuing the following command as root for each disk:
   db2cluster -cfs -remove -filesystem <fs-name> -disk <disk-path>
   
   Note: The above command should be run sequentially for each disk.
   
6. Repeat the fifth step on each file system