Hitachi MP-96RD625-01 manual Pair Status

As shown in Figure 2-8, after delta resync operation is performed properly and the primary site A is recovered from the failure, then the URz pair between the primary site A and the URz secondary site will be the pair for delta resync operation and become prepared for the failure in the primary site B. For information about the requirements to perform delta resync operation properly, see section Requirements for Performing Delta Resync Operation.

Pair Status

URz displays the pair status for each data volume of specified CU Image (CUI) in the connected USP V storage system. Table 2-4 lists and describes the URz data volume pair status descriptions. The primary storage system maintains the status of the primary data volume and can change the pair status of the primary data volume and secondary data volume. The secondary storage system maintains the status of the secondary data volume and can change the pair status of the secondary data volume but not the primary data volume. The primary storage system will detect when the secondary storage system changes the secondary data volume status (if the path status is normal) and will change the primary data volume status accordingly. You can display the detailed pair status information at the Storage Navigator remote console PC (URz Pairdisplay window) or at the host processor (Business Continuity Manager Pairdisplay command).

A volume which is not assigned to a URz data volume pair has the status simplex. When a URz data volume pair is started, the primary storage system changes the status of the primary data volume and secondary data volume to pending duplex. When the initial copy operation is complete, the primary storage system changes the status of both data volumes to duplex. When a pair is suspended from the primary storage system, the primary storage system changes the status of the primary data volume and secondary data volume (if the path status is normal) to suspended. When a pair is suspended from the secondary storage system, the secondary storage system changes the status of the secondary data volume to suspended, and the primary storage system detects the pair suspension (if the path status is normal) and changes the primary data volume status to suspended. When you release a pair from the primary storage system, the primary storage system changes the status of the primary data volume and secondary data volume (if the path status is normal) to simplex. When you release a pair from the secondary storage system, the secondary storage system changes the secondary data volume status to simplex, and the primary storage system detects the pair release (if the path status is normal) and changes the primary data volume status to suspended.

When a URz data volume pair is split or suspended, the primary storage system generates a service information message (SIM) to notify the host(s). If SNMP is installed and operational for USP V, this SIM results in an SNMP trap which indicates the reason for suspension.

Chapter 2 About Universal Replicator Operations 2-33

Hitachi Universal Replicator for IBM /OS User’s Guide