Dynamic storage reconfiguration

Dynamic storage reconfiguration allows central storage allocated to an LP to be changed while the LP is active. It is supported in Linux® and General LPs running z/OS®. Dynamic storage reconfiguration is not supported in coupling facility or Linux-Only LPs. z/VM® 7.1 and later support dynamic storage reconfiguration (for central storage only) in any partition mode.

Dynamic storage reconfiguration provides the capability to reassign storage from one LP to another without the need to POR the CPC or IPL the recipient LP. Every LP has a storage range definition consisting of an origin, initial, and reserved amounts. The reserved value determines how much additional storage can be acquired using dynamic storage reconfiguration.

Storage is released when an LP is either deactivated or its reserved storage element is deconfigured. Additionally, you can release central storage in amounts smaller than the defined storage element size.

With dynamic storage reconfiguration, General LPs can have reserved amounts of central storage. This storage can become available to the LP if no other active LP has this reserved storage online. Reserved central storage can be made available to the LP by commands from the operating system console.

If the operating system running in the LP supports physical storage reconfiguration, use operating system commands to make the reserved storage available to the LP without disrupting operating system activities.

For z/OS, use the following command format to reconfigure central storage:

     CF STOR(E=1),<OFFLINE/ONLINE>

Dynamic storage reconfiguration on the mainframes for central storage enables central storage to be reassigned between LPs that have noncontiguous address ranges. In this case, PR/SM can allocate a hole or some set of central storage addresses for which there is no backing physical storage assigned. Later, PR/SM is able to configure storage online to the LP by assigning some physical central storage to the hole.

For central storage, you can reconfigure central storage in amounts equal to the storage granularity supported by the CPC. For z/OS, use the following command format:

     CONFIG STOR(nnM),<OFFLINE/ONLINE>

For more information on using the commands see Device Drivers, Features, and Commands Reference.