You can specify whether the host can access the P-VOL when the pair is split due to an error. Select one of the following fence level options by running the raidcom add remote_copy_pair command with the -fence_level option.
- Data: The P-VOL is fenced when an update copy operation fails. This prevents the host from writing to the P-VOL during a failure. This setting should be considered for the most critical volumes for disaster recovery. This setting reduces the amount of time required to analyze the consistency of S-VOL data with the P-VOL during disaster recovery efforts.
This setting is functionally equivalent to the CRIT(YES-ALL) parameter for the CESTPAIR command.
- Status: The P-VOL is fenced only if the primary system is not able to change S-VOL status to Suspend when an update copy operation fails. If the primary system successfully changes S-VOL pair status to Suspend, subsequent write I/O operations to the P-VOL will be accepted, and the system will keep track of updates to the P-VOL. This allows the pair to be resynchronized quickly. This setting also reduces the amount of time required to analyze S-VOL consistency during disaster recovery.
This setting is functionally equivalent to the CRIT(YES PATHS) parameter for the CESTPAIR command.
- Never: The P-VOL is never fenced. This setting should be used when I/O performance outweighs data recovery. "Never" ensures that the P-VOL remains available to applications for updates, even if all TrueCopy for Mainframe copy operations have failed. The S-VOL might no longer be in sync with the P-VOL, but the primary system keeps track of updates to the P-VOL while the pair is suspended. Host failover capability is essential if this fence level setting is used. For disaster recovery, the consistency of the S-VOL is determined by using the sense information transferred by host failover or by comparing the S-VOL contents with other files confirmed to be consistent.
This setting is functionally equivalent to the CRIT(NO) parameter for the CESTPAIR command.