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Functional and Operational Characteristics 3-13
Hitachi Universal Storage Platform V/VM User and Reference Guide
Mode Category Function Default MCU/RCU
460 SM SVP
When turning off PS, the control information of the following
software stored in shared memory will be backed up in SVP.
After that, when performing volatile PS ON, the control
information will be restored into shared memory from SVP.
TrueCopy, TrueCopy for z/OS, ShadowImage, ShadowImage for
z/OS, Volume Migration, FlashCopy, Universal Replicator,
Universal Replicator for z/OS, COW Snapshot
Setting Mode 460 to ON is required to enable the function.
Note: This support only applies to the case of volatile PS ON
after PS OFF. As usual, power outage, offline micro-program
exchange, DCI and System Tuning are not supported.
Note: Since PS-OFF/ON takes up to 25 minutes, when using
power monitoring devices (PCI, etc.), it is required to take
enough time for PS-OFF/ON.
OFF –
464 TrueCopy for z/OS SIM Report without Inflow Limit
For TrueCopy for z/OS, the SIM report for the volume without
inflow limit is available when mode 464 is set to ON.
SIM: RC=490x-yy (x=CU#, yy=LDEV#)
OFF MCU
466 UR/URz
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
SI/SIz, FlashCopy,
COW 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 z/OS, FlashCopy, Copy-on-
Write 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 –