Hitachi Virtual Storage Platform F400, Руководство системного администратора

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Mode Category Description Default MCU/RCU
467 ShadowImage
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.
■
SI
■
Snapshot
■
UVM
■
Volume Migration
Mode 467 = ON (default): 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 SOM must always be set to ON when
using an external volume as the secondary volume
of any of the applicable replication products.
Notes:
1. It takes longer to finish the copy processing
because it stops for prioritizing the host I/O
performance.
2. This SOM supports background copy only. The
processing to copy the pre-update data to the S-
VOL, which occurs when overwriting data to
uncopied slots of P-VOL in Split processing or
reading or writing data to uncopied slots of S-
VOL, is not supported.
3. Check the write pending rate of each CLPR per
MP blade. Even though there is some free cache
capacity in the entire system, if the write
pending rate of an MP blade to which pairs*
belong exceeds the threshold, the copy
operation is stopped.
*Applies to pairs of SI, SIz, FCv2, FCSE, Snapshot,
and Volume Migration.
ON -
System option modes
Appendix B: System option modes
System Administrator Guide for VSP Gx00 models and VSP Fx00 models 299