Functional and Operational Characteristics
2–17
Hitachi VSP User and Reference Guide
466 Universal
Replicator,
Universal
Replicator for
Mainframe
For UR/URz operations it is strongly recommended
that the path between main and remote storage
systems have a minimum data transfer speed of
100 Mbps. If the data transfer speed falls to 10
Mbps or lower, UR operations cannot be properly
processed. As a result, many retries occur and UR
pairs may be suspended. Mode 466 is provided to
ensure proper system operation for data transfer
speeds of at least 10 Mbps.
Mode 466 = ON: Data transfer speeds of 10 Mbps
and higher are supported. The JNL read is
performed with 4-multiplexed read size of 256 KB.
Mode 466 = OFF: For conventional operations.
Data transfer speeds of 100 Mbps and higher are
supported. The JNL read is performed with 32-
multiplexed read size of 1 MB by default.
Note: The data transfer speed can be changed
using the Change JNL Group options.
OFF
467 ShadowImage,
ShadowImage
for
Mainframe,Co
mpatible
FlashCopy®
V2, Snapshot,
Volume
Migration,
Universal
Volume
Manager
For the following features, the current copy
processing slows down when the percentage of
“dirty” data is 60% or higher, and it stops when the
percentage is 75% or higher. Mode 467 is provided
to prevent the percentage from exceeding 60%, so
that the host performance is not affected.
ShadowImage, ShadowImage for Mainframe,
Compatible FlashCopy® V2, Snapshot, Volume
Migration, Universal Volume Manager
Mode 467 = ON: Copy overload prevention. Copy
processing stops when the percentage of “dirty”
data reaches 60% or higher. When the percentage
falls below 60%, copy processing restarts.
Mode 467 = OFF: Normal operation. The copy
processing slows down if the dirty percentage is
60% or larger, and it stops if the dirty percentage is
75% or larger.
Caution: This mode must always be set to ON when
using an external volume as the secondary volume
of any of the above-mentioned replication products.
Note: It takes longer to finish the copy processing
because it stops for prioritizing the host I/O
performance.
ON
Mode Category Description Default MCU/RCU
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