HP XP7 Storage - Manual (Page 92)

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If power is removed from a secondary system or from a data path component while Cnt Ac-S
Z operations are in progress, the primary system detects the communication failure, splits all
affected pairs, and generates SIMs reporting the failures. The primary system changes the
P-VOL status to Suspended-by Remote Storage System but cannot change the status of the
S-VOLs.
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If a primary is powered off and the backup batteries are fully discharged while pairs are split,
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 primary system
A planned outage of the primary system does not affect Continuous Access Synchronous Z.
Planned outage of the secondary system or remote path
You must split the pairs in a secondary system prior to a planned outage of the system or to a data
path component (for example, switch, channel extender).
Procedure 31 To perform a planned outage of a secondary system or data path component
1. Identify the P-VOLs that are paired with S-VOL in the secondary system that is to be powered
off.
For data path outage, identify all P-VOLs in the primary 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 primary system that contains affected P-VOLs, and split all affected pairs.
Confirm the changed pair status.
3. Perform the planned outage of the secondary system or data path.
4. When the secondary system is fully powered on and ready, resynchronize the affected pairs
at each primary system. Confirm the pair status changes.
Planned outage of both primary and secondary systems
When you plan an outage of a Continuous Access Synchronous Z primary and secondary systems
at the same time, the primary system must be powered off first, and then powered on last.
Procedure 32 To perform a planned outage of primary and secondary system
1. Perform the planned outage of the primary system first. Because a planned outage does not
affect pairs, nothing out of the ordinary must be done regarding the Cnt Ac-S Z system or
operations. Do not power on the primary system at this time.
2. If a secondary system to be powered off is connected to a primary system that is not powered
off, split the pairs before powering off the secondary system. Confirm that the pair status
changes.
3. Perform the planned outage of the secondary systems as described in “Planned outage of the
secondary system or remote path” (page 92) .
4. Power on the secondary systems. Make sure that they are fully operational and ready to
resynchronize operations before powering on the primary system.
5. Power on the primary system, and make sure it is ready to resynchronize operations. If you
split any pairs in step 2, you can also resynchronize those pairs now.
92 Monitoring and maintaining the Cnt Ac-S Z system