Hitachi G1000 - GAD pair operations

• When the pair status is INIT/COPY, read/write continues to the P-VOL.
Read/write to the S-VOL remains stopped.
• When the pair status is PSUS, PSUE, SSWS, or SSUS, read/write
continues to the volume whose I/O mode is Local. Read/write is stopped
to the volume whose I/O mode is Block.
Related topics
•
Quorum disk and server I/O on page 1-17
I/O stoppage not detected in the counterpart system
When a stoppage is not detected within 5 seconds in the counterpart system,
the pair volume whose system wrote the communication stoppage to the
quorum disk will continue to receive read/write after the stoppage. Read/
write processing depends on the pair status and I/O mode of the volume that
did not detect the write.
• When the pair status is PAIR, read/write continues.
• When the pair status is INIT/COPY, read/write continues to the P-VOL.
Read/write to the S-VOL remains stopped.
• When the pair status is PSUS, PSUE, SSWS, or SSUS, read/write
continues to the volume whose I/O mode is Local. Read/write is stopped
to the volume whose I/O mode is Block.
In addition, server I/O does not continue to the volume that should have
notified the quorum disk, but did not, that it cannot accept I/O, because
either a storage system failure occurred or the quorum disk is no longer
accessible.
Related topics
•
Quorum disk and server I/O on page 1-17
GAD pair operations
The GAD pair operations are:
• Pair creation: copies the data in a volume in the primary system to a
volume in the secondary system. Before a pair is created, the GAD
reservation attribute must be applied to the volume that will become the
S-VOL.
WARNING: Pair creation is a destructive operation. When a pair is
created, the data in the S-VOL is overwritten by the data in the P-VOL.
Before you create a pair, you are responsible for backing up the data in a
volume that will become an S-VOL as needed.
• Pair suspension: stops write data from being copied to the S-VOL. When
you suspend a pair, you can specify the volume (P-VOL or S-VOL) that
will receive update data from the host while the pair is suspended. If you
Overview of global-active device
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Hitachi Virtual Storage Platform G1000 Global-Active Device User Guide