GPFS file system rebalancing check Changing Physical Disk Storage in IBM DB2 pureScale: A Practical Example 4 After the disks are added to a file system, the data on existing disks should be rebalanced to the new  disks. Automatic GPFS rebalancing might happen, depending on the storage disk vendors that are added. For  example, there were four findings during this case scenario test: No matter what the storage product is, the necessary actions are clear: After you add the new EMC disks, the new disk status changes to  ready  and the free size on the disks is  100%, which means these disks are empty and that the GPFS rebalancing did not happen in this case  (see Figure 3). To start the GPFS rebalancing manually, run the following command as root: # db2cluster -cfs -rebalance -filesystem db2data4 Figure 3. Check whether the GPFS rebalancing started When you add new EMC DMX disks on a file system that consists of IBM DS8000 storage disks,   GPFS rebalancing does not start automatically. When you add IBM DS8000 storage disks on a file system that consists of IBM DS8000 storage   disks, GPFS rebalancing starts automatically. When you add new EMC DMX disks and IBM DS8000 storage disks, after you add the new EMC   DMX disks to a file system, GPFS rebalancing does not start automatically even if you add IBM  DS8000 storage disks afterward. When you add new EMC DMX disks on a file system that consists of EMC DMX storage disks, GPFS   rebalancing does not start automatically. Check whether the rebalancing is in progress after you add the new disks.  If the GPFS rebalancing is activated, let it run. Otherwise, start the GPFS rebalancing manually. 