Concurrent maintenance

From packaging displays

This option provides the capability to power off a subset of the system and perform service actions on hardware in that subset. Other parts of the system remain powered on and functional. Service actions supported include replacement, upgrade, removal, addition, and movement of hardware.

The subset of system hardware that you power off in order to shut down a particular piece of hardware is known as the power domain for that piece of hardware. The power domain of a piece of hardware is determined by the granularity of the power control system. For example, the power domain of an I/O processor on an SPD bus is the frame in which the SPD bus resides. This is because the power control system for SPD buses does not support powering individual I/O processor slots on and off. In contrast, the power control system for PCI buses does support powering individual I/O card slots on and off. Consequently, the power domain for an I/O card on a PCI bus is the card itself.

There are some restrictions on hardware resource concurrent maintenance which are enforced by the operating system.

Some of the more common restrictions are as follows:

• You cannot power off some I/O towers without powering off the entire system.
• If you are powering off a power domain containing configured disk units that are not mirrored in a different power domain, it is likely that a disk unit attention SRC will appear in the operator panel display. Also, some or all system activity could stop until the domain is powered back on and the disk units become available again. The I/O processors and I/O adapters to which these disk units are attached may only be replaced while the domain is powered off. Any other actions on these hardware resources are unsupported and may cause failures requiring a system IPL to recover. There are no restrictions on the service actions that can be performed on other hardware resources in the power domain.
• A power domain containing hardware resources that are in use by the operating system cannot be powered off. All configuration objects using hardware resources in the power domain must be varied off before the power domain can be powered off.
• You must end all active CRGs (cluster resource groups) prior to attempting to power off a power domain using concurrent maintenance.
• The system you are using must be the SPCN (system power control network) for the selected power domain.
• A power domain containing switchable bus adapters cannot be powered off if any of the bus adapters are owned by a system other than the one you are using.

You can find more information on these restrictions by pressing F1 at the Concurrent Maintenance display.