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
96 HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software
Command Line Interface Reference Guide
Note: The NOWRITEBACK_CACHE switch is the default on transportable disks. The
WRITEBACK_CACHE switch is the default on
NOTRANSPORTABLE disks.
■ Specify WRITEBACK_CACHE for all new RAIDsets, mirrorsets, and
units that you want to take advantage of the controller writeback caching
feature.
■ Specify NOWRITEBACK_CACHE for units that you want data from the
host to go directly to the specified devices without being cached.
Caution: Although there is built-in redundancy to protect data contained in
cache, allowing data to be written to writeback cache can result in the loss of
data if the controller fails.
Specifying NOWRITEBACK_CACHE 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. This process is called
write-through caching because the data passes through—and is stored in—the
cache memory on its way to the disk drives. Write-through caching is only
enabled after writeback caching is disabled, or after the
MAXIMUM_CACHED_TRANSFER_SIZE switch is set to zero.
Note: The controller can take up to five minutes to flush data contained within the
writeback cache if you specify the NOWRITEBACK_CACHE switch.
Examples
To create unit D102 from a single disk drive named DISK10000, enter:
ADD UNITS D102 DISK10000
■ If the controller pair is in Transparent Failover mode, this unit is on
port 2. It is presented to each host connection as LUN (2 – offset). Offset
is a host connection characteristic, specified in the ADD CONNECTIONS
(or SET connection-name) command.