HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Command Line Interface Reference Guide (EK-G80CL-RA. C01, March 2005)

CLI Command Descriptions
243HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software
Command Line Interface Reference Guide
WRITEBACK_CACHE (default)
NOWRITEBACK_CACHE
Enables or disables the writeback data caching function of the controller.
Controller writeback caching feature improves write performance.
■ Specify WRITEBACK_CACHE for all new RAIDsets, mirrorsets, and
units to take advantage of the controller writeback caching feature. This
switch allows the controller to declare the write operation complete as
soon as the data reaches its cache memory. The controller performs the
slower operation of writing the data to the disk drives at a later time.
Caution: Though there is built-in redundancy in mirrored cache to protect
data, allowing data to be written to writeback cache can result in the loss of
data if the cache fails.
WRITEBACK_CACHE cannot be applied to transportable disks.
The NOWRITEBACK_CACHE switch enables only write-through caching. In
write-through caching, if the controller receives a write request from the host
it places the data in its cache module, writes the data to the disk drives, and
then notifies the host if the write operation is complete. Write-through caching
is enabled only if writeback caching is disabled.
NOWRITEBACK_CACHE is the default on transportable disks.
Note: If you use the NOWRITEBACK_CACHE switch, the controller can take 5
minutes to flush data contained within the writeback cache.
Examples
To enable write protect and turn off the read cache on unit D102, enter:
SET D102 WRITE_PROTECT NOREAD_CACHE
To allow only a host connection named Roger1 to access unit D0, enter:
SET D0 DISABLE_ACCESS_PATH=ALL
SET D0 ENABLE_ACCESS_PATH=ROGER1