HP XP7 Continuous Access Synchronous User Guide (TK911-96004)

Split types
This topic discusses pairs that are split by user operation (PSUS ), and pairs that are suspended
by the system because of failure (PSUE).
• You can split a pair when the initial copy operation is complete.
You must split a pair to perform media maintenance on the P-VOL or to access the S-VOL
(when S-VOL write is enabled).
◦
◦ When you split a pair, the primary system ensures synchronization by completing any
pending update copy operation before changing the status to PSUS.
• Pairs are split by the primary system only, for any of the following reasons:
You released the pair from the secondary system.◦
◦ An error condition related to the secondary system, the S-VOL, or an update-copy
operation.
◦ The primary system cannot communicate with the secondary system.
Split types appear in the Status field on the View Pair Properties window. The following table
describes the split types.
DescriptionVolume applies
to
PSUS type
The user split the pair from the primary system specifying Disable for Primary
Volume Write. The S-VOL split type is "by Local Storage System"
P-VOLPrimary Volume by
Operator
The user split the pair from the primary or secondary system specifying Disable
for Primary Volume Write.
P-VOL
S-VOL
Secondary Volume by
Operator
The secondary system received a request from the primary system to split the
pair. The P-VOL split type is Primary Volume by Operator or Secondary
Volume by Operator.
S-VOLby Local Storage
System
The primary system detected that the S-VOL status changed to SMPL because
you released the pair from the secondary system. The pair cannot be
resynchronized because the S-VOL does not have the PSUE/PSUS status.
P-VOLRelease pair to RCU
The primary system detected an error condition at the secondary system
(RCU), that caused the primary system to split the pair. The S-VOL split type
is S-VOL Failure by Local Storage System.
P-VOL
S-VOL
by Remote Storage
System
The primary system detected an error during communication with the
secondary system, or an error during update copy. In this case, the S-VOL
P-VOL
S-VOL
S-VOL failure
split type is usually S-VOL Failure. This split type is also used when the number
of paths falls below the minimum number of paths setting on the Add Remote
Connection window.
The primary system could not find valid control information in its nonvolatile
memory during IMPL. This condition occurs only if the primary system is
P-VOL
S-VOL
MCU IMPL
without power for more than 48 hours (that is, power failure and fully
discharged backup batteries).
The pair was split before the initial copy operation was complete. The data
on the S-VOL is not identical to the data on the P-VOL.
P-VOL
S-VOL
Initial copy failed
62 Monitoring and maintaining the Cnt Ac-S system