HP XP Racks - Manual (Page 122)

Description Item
Cache Mode • Enable: Write data from the host is propagated asynchronously
•
Disable: Write data from the host is propagated synchronously
When Online Migration is specified as the Attribute, the cache modes are
displayed.
•
Through: Transfers write and read requests from the host to the external
storage system. The local system’s cache is not used.
• Write Sync: Reflects write data from the host to the external storage
system synchronously. If read or write is performed while data is being
written to the external storage system, the read or write operation waits
until the ongoing write operation is completed.
While cache mode operations are in progress, status is reported for cache
mode changes.
• (Changing): Transition to the displayed cache mode is in progress.
•
(Error): Transition to the displayed cache mode has failed and
maintenance work is required.
See “Cache use and external storage performance” (page 14) for more
information.
Inflow Control •
Enable: Limits or prevents write data from being written to cache memory
when the write operation cannot be performed.
•
Disable: Allows write data to be written to cache when the write
operation cannot be performed.
See “Editing external volume policies (settings)” (page 42) for more
information.
Displays the external path of the external volume. Path Mode
•
Single: One external path is used, with alternate paths available in case
of failure.
•
Multi: Multiple paths are used at the same time.
•
ALUA: Like Multi, all paths are used; however, they are not used when
connected to ports in Passive status. For more information, see
“External
paths” (page 21) .
Displays whether ALUA can be set as the Path Mode in the local storage
system. ALUA Permitted
• Enable: ALUA Mode is used.
•
Disable: ALUA Mode is not used.
Displays I/O load balance system for external storage system. Load Balance Mode
• Normal Round-robin: Performs load balance in round-robin system.
•
Extended Round-robin: Load balance system is automatically switched
for sequential I/O and random I/O.
• Disable: Performs I/O operation with a single path, without load balance.
Edit External Path Configuration wizard
Use this wizard to add and remove external paths to a path group, and to raise and lower path
priority.
See
“Adding an external path to an existing path group ” (page 50) for instructions.
The windows in the wizard are:
•
“Edit External Path Configuration window” (page 123)
•
“Confirm window” (page 125)
122 External Storage GUI reference