IBM SY44-5902-05 manual Start device parity protection, Stop device parity protection

Work with device parity protection: Select this option to perform the system functions that handle device parity protection on the system. Device parity protection is a data redundancy feature available on some storage media units. It is maintained across all the units that are within the parity set. If one unit fails, the units within the set handle the functions for the failed unit. This type of protection can improve system availability and reduce the possibility of data loss. The following options are available:

vDisplay device parity status

Select this option to show the status of disk unit subsystems that have device parity protection.

vStart device parity protection

Use this option to begin the process of protecting data on the system.

vStop device parity protection

This option allows you to end device parity protection.

vInclude unit in device parity protection

This option allows you to add an unprotected disk unit to an existing parity set.

vExclude unit in device parity protection

This option allows you to remove a disk unit from a parity set.

Work with disk compression: Select this option to display disk compression status, or select this option to start or stop disk compression.

The following options are available:

vDisplay disk compression

Select this option to display the status of compressed disks.

vStart compression on disk units

Select this option to start compression on disk units. This will increase the effective size of the disk unit.

vStop compression on disk units

Select this option to stop compression on disk units.

Work with disk unit recovery: Select the Work with Disk Unit Recovery display from the Work with disk units option on the Use Dedicated Service Tools (DST) display. Options are available to save and restore disk units, find and assign disk units that are missing from the configuration, replace disk units, reclaim IOP cache storage, and recover the system configuration if it is lost, destroyed, or changed.

vSave disk unit data

Run this option when the disk unit reference code (URC) indicates that a disk enclosure should be exchanged.

Before removing the disk enclosure and installing a new disk enclosure, you should save the data from the disk units in the disk enclosure to removable media.

When the system has saved all of the disk unit data to removable media, an ending display appears with the status information.

Note: This procedure does not save the Licensed Internal Code on the load-source disk unit.

Note: The option is not allowed for disk units that have device parity protection or mirror protection (with both units in an active state.)

vRestore disk unit data

20Service Functions V5R2