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 access a volume which has the Secondary Volume Write option enabled.
- To synchronize data of the primary and secondary sites after the split, complete the update copy operation before splitting a pair.
- 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.
|
Split type |
Volume applies to |
Description |
|---|---|---|
|
Primary Volume by Operator |
P-VOL |
The user split the pair from the primary system specifying Disable for Primary Volume Write. The S-VOL split type is by MCU. |
|
Secondary Volume by Operator |
P-VOL S-VOL |
The user split the pair from the primary or secondary system specifying Depends on Primary Volume Fence Level for Primary Volume Write. |
|
by MCU |
S-VOL |
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. |
|
Release pair to RCU |
P-VOL |
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. |
|
by RCU |
P-VOL S-VOL |
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 Secondary Volume Failure. |
|
Secondary Volume Failure |
P-VOL S-VOL |
The primary system detected an error during communication with the secondary system, or an error during update copy. In this case, the S-VOL split type is usually Secondary Volume 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. |
|
MCU IMPL |
P-VOL S-VOL |
The primary system could not find valid control information in its nonvolatile memory during IMPL. This condition occurs only if the primary system is without power for more than 48 hours (that is, power failure and fully discharged backup batteries). |
|
Initial Copy Failed |
P-VOL S-VOL |
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. |