Hitachi Virtual Storage Platform, Руководство пользователя и справочник

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Functional and Operational Characteristics
2–21
Hitachi VSP User and Reference Guide
491 ShadowImage
ShadowImage
for Mainframe Mode 491 is used for improving the performance of
ShadowImage/ ShadowImage for Mainframe/
ShadowImage FCv1.
Mode ON: The option (Reserve05) of
ShadowImage/ ShadowImage for Mainframe is
available. If the option is set to ON, the copy of
ShadowImage/ ShadowImage for Mainframe/
ShadowImage FCv1 will be performed from 64
processes to 128 processes so that the performance
will be improved.
Mode OFF (default): The option (Reserve05) of
ShadowImage/ ShadowImage for Mainframe is
unavailable. The copy ofShadowImage/
ShadowImage for Mainframe/ ShadowImage FCv1
is performed with 64 processes.
Note:
1. Make sure to apply mode 491 when the
performance of ShadowImage/ ShadowImage for
Mainframe/ ShadowImage FCv1 is considered to be
important.
2. Make sure not to apply the mode when the host
I/O performance is considered to be important.
3. The mode will be noneffective if 3 or more pairs
of DKAs are not mounted.
4. Make sure to set mode 467 to OFF when using
mode 491, since the performance may not improve.
5. The mode is noneffective for the NSC model.
OFF .
495 NAS Function:
That the secondary volume where S-VOL Disable is
set means the NAS file system information is
imported in the secondary volume. If the user has
to take a step to release the S-VOL Disable attribute
in order to perform the restore operation, it is
against the policy for the guard purpose and the
guard logic to have the user uninvolved. In this
case, in the NAS environment, Mode 495 can be
used to enable the restore operation.
Mode 495 = ON:
The restore operation ?Reverse Copy, Quick
Restore) is allowed on the secondary volume where
S-VOL Disable is set.
Mode 495 = OFF (default):
The restore operation ?Reverse Copy, Quick
Restore) is not allowed on the secondary volume
where S-VOL Disable is set.
OFF
Mode Category Description Default MCU/RCU