HP StorageWorks XP Remote Web Console Software - Manual (Page 58)

2-36 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
Suspend Types
Table 2-5 lists and describes the URz suspend types, which indicate the reason
for the suspension. A URz pair can be suspended by the user at any time after
the initial copy operation is complete. The user must suspend a URz pair in
order to perform ICKDSF maintenance on the primary data volume or to
access the secondary data volume (read only mode).
When a URz pair is suspended by the user, the primary storage system and
secondary storage system ensure synchronization by either completing or
discarding any pending update copy operations according to the user-specified
drain/purge suspend option.
A URz pair is suspended by the primary storage system when the following
suspension conditions are detected. A URz pair can also be suspended by the
secondary storage system (see section Suspension Condition).
• When the primary storage system detects that the user has released the
volume pair from the secondary storage system (e.g., to access an
secondary data volume at the secondary site),
• When the primary storage system detects an error condition related to the
secondary storage system, secondary data volume, or a URz journal data
operation,
• When the secondary storage system cannot execute DFW (DASD fast
write) to the secondary data volume (only if DFW required is selected), or
• When the primary storage system is unable to communicate with the
secondary storage system.
For more information on URz journal data operations, see section Suspension
Condition.
When a URz pair is suspended, the primary storage system stops performing
update copy operations to the secondary data volume. Moreover, the primary
storage system and secondary storage system keep track of any journal data
that were discarded during suspension, and the primary storage system
continues accepting write I/Os for the primary data volume and keeps track of
the primary data volume tracks which are updated while the pair is suspended.
A suspended URz secondary data volume has an additional status called the
consistency status which is displayed only at the secondary storage system. The
consistency status of a suspended URz secondary data volume indicates its
update sequential consistency with respect to the other secondary data volumes
in the same group.
Table 2-7 lists and describes the consistency status descriptions for suspended
URz secondary data volumes.
When a URz pair is suspended, whether user-requested or due to failure, the
primary storage system generates sense information to notify the host(s).