PSUS 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 Disable 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.
Delete 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 S-VOL
Failure by Local Storage System.
S-VOL 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 S-VOL 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.
System behavior
Note the following behaviors for split pairs:
• The primary system stops performing update operations to the S-VOL. It
may or may not continue accepting write I/Os to the P-VOL depending on
the P-VOL fence level setting.
• If an update fails, the primary system reports a unit check and notifies
the host that Write fails. This ensures that both the host system and
application program regard the write operation to the P-VOL as failed.
• If the primary system accepts subsequent write I/Os for a split P-VOL, the
system records the updated data in the P-VOL tracks as differential data.
When a split pair is resynchronized, the primary system copies the out of
sync P-VOL tracks to the S-VOL as differential data.
7-6
Monitoring and maintaining the TC system
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models
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