HP XP P9000 Continuous Access Synchronous for Mainframe Systems User Guide

General information
Please review the following system behaviors regarding powering off:
• Cnt Ac-S Z pairs are not affected when power is removed from a main system while operations
are in progress.
• When power is restored on the main system, the system communicates with the remote systems
to confirm S-VOL pair status(es). Make sure that Cnt Ac-S Z communications are fully restored
(all paths have normal status) before beginning I/O operations to the P-VOL.
If the main system accepts an I/O for a P-VOL before this, all communications are restored,
and the main system will suspend the pair and change P-VOL status to Suspended-by RCU.
The main system cannot change the pair status of the S-VOL.
• If power is removed from a remote system or from a data path component while Cnt Ac-S Z
operations are in progress, the main system detects the communication failure, suspends all
affected pairs, and generates SIMs reporting the failures. The main system changes the P-VOL
status to Suspended-by RCU but cannot change the status of the S-VOLs.
• If a main or remote system is powered off and the backup batteries are fully discharged while
pairs are suspended, differential data is retained to SSD. In this unlikely case, MCU copies
differential data to RCU when the pairs are resynchronized.
Planned outage of the main system
A planned outage of the main system does not affect Cnt Ac-S Z.
Planned outage of the remote system or data path
You must split the pairs in a remote system prior to a planned outage of the system or to a data
path component (for example, switch, channel extender).
Procedure 23 To perform a planned outage of a remote system or data path component:
1. Identify the Cnt Ac-S Z P-VOLs that are paired with S-VOL in the remote system that is to be
powered off.
For data path outage, identify all P-VOLs in the main system that use the path or component
to be powered off.
You need to know the MCU, CU, and LDEV ID for each of the P-VOLs.
2. Connect to each main system that contains affected P-VOLs, and split all affected Cnt Ac-S Z
pairs. Confirm the changed pair status.
3. Perform the planned outage of the remote system or data path.
4. When the remote system is fully powered on and ready, resynchronize the affected pairs at
each main system. Confirm the pair status changes.
Planned outage of both main and remote systems
When you plan an outage of a Cnt Ac-S Z main and one or more remote systems at the same
time, the main system must be powered off first, and powered on last.
Procedure 24 To perform a planned outage of Continuous Access Synchronous Z main and remote
system:
1. Perform the planned outage of the main system first. Because a planned outage does not affect
Cnt Ac-S Z pairs, nothing out of the ordinary must be done regarding the Cnt Ac-S Z system
or operations. Do not power on the main system at this time.
2. If a remote system to be powered off is connected to a main system that is not powered off,
suspend the Cnt Ac-S Z pairs before powering off the remote system. Confirm that the pair
status changes.
Managing power-off for systems and network devices 87