User guide

B–6 System option modes
Hitachi Unified Storage VM Block Module Hardware User Guide
457 ESM The high speed LDEV format for external volumes is
available by setting System Option Mode 457 to ON.
When Mode 457 is ON and you select the external
volume group and format an LDEV, any Write processing
on the external LUs will be skipped.
Mode 457 = ON: High speed LDEV format for external
volumes is supported . Control Block Write of external
LDEVs in Mainframe emulation is supported by Storage
Navigator.
When the LDEV is not written with data “0” before
performing the function, the LDEV format may fail.
After the formatting is complete, set System Option
Mode 457 to OFF.
OFF Both
459 ShadowImage When the secondary volume of an SI/SIz pair is an
external volume, the transaction to change the status
from SP-PEND to SPLIT is as follows:
1. Mode 459 = ON when creating an SI pair: The copy
data is created in cache memory. When the write
processing on the external storage completes and
the data is fixed, the pair status will change to SPLIT.
2. Mode 459 = OFF when creating an SI/SIz pair Once
the copy data has been created in cache memory, the
pair status will change to SPLIT. The external storage
data is not fixed (current spec).
OFF -
466 Universal
Replicator
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
Mode Category Description Default
MCU/
RCU