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Chapter 2 About Universal Replicator Operations 2-33
Hitachi Universal Replicator for IBM /OS User’s Guide
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.