Dynamic volume expansion

Dynamic volume expansion is the capability to increase provisioned capacity up to a maximum size while volumes are online to a host and not in a Copy Services relationship.

Dynamic volume expansion increases the capacity of open systems, IBM® i, and IBM Z volumes, while the volume remains connected to a host system. This capability simplifies data growth by providing volume expansion without taking volumes offline.

Some operating systems do not support a change in volume size. Therefore, a host action is required to detect the change after the provisioned capacity is increased.

The following volume sizes are the maximum that are supported for each storage type.
  • Open systems FB volumes: 16 TB
  • IBM i variable size volumes
  • IBM Z CKD volume types 3390 model 9 and custom: 65520 cylinders
  • IBM Z CKD volume type 3390 model 3: 3339 cylinders
  • IBM Z CKD volume types 3390 model A: 1,182,006 cylinders
Note: Volumes cannot be in Copy Services relationships (point-in-time copy, FlashCopy® SE, Metro Mirror, Global Mirror, Metro/Global Mirror, and z/OS® Global Mirror) during expansion.