Cache-Parameter; Cache-Parameter Properties - HP P2000 Reference Manual

cache-parameter

Properties
Table 12

cache-parameter properties

Name
serial-number
volume-name
write-policy
write-policy-
numeric
cache-
optimization
cache-
optimization-
numeric
read-ahead-size
read-ahead-
size-numeric
296 XML API basetype properties
Type Description
If a volume is specified, its serial number.
string
If a volume is specified, its name.
string
If a volume is specified, its cache write policy.
string
• write-back: Write-back caching does not wait for data to be completely
written to disk before signaling the host that the write is complete. This is the
preferred setting for a fault-tolerant environment because it improves the
performance of write operations and throughput. This is the default.
• write-through: Write-through caching significantly impacts performance
by waiting for data to be completely written to disk before signaling the host
that the write is complete. Use this setting only when operating in an
environment with low or no fault tolerance.
Numeric equivalents for write-policy values.
string
•
0: write-through
•
1: write-back
If a volume is specified, its cache optimization mode.
string
• standard: Optimizes cache for both sequential and random reads. Used
for applications that read and write small files in random order, such as
transaction-based and database update applications. This is the default.
• super-sequential: Optimizes cache for sequential reads only. Used for
applications that read and write large files in sequential order, such as video
playback and multimedia post-production video and audio editing
applications.
Numeric equivalents for cache-optimization values.
string
•
0: standard
•
1: super-sequential
If a volume is specified, its read-ahead cache setting.
string
• Disabled: Read-ahead caching is disabled.
• Default: One chunk for the first access in a sequential read and one stripe
for all subsequent accesses.
• Maximum: Maximum read-ahead size calculated by the controller.
•
64 KB, 128 KB, 256 KB, 512 KB, 1 MB, 2 MB, 4 MB, 8 MB, 16 MB, 32
MB: Size selected by a user.
Numeric equivalents for read-ahead-size values.
string
•
-1: Default
•
0: Disabled
•
65536: 64 KB
•
131072: 128 KB
•
262144: 256 KB
•
524288: 512 KB
•
1048576: 1 MB
•
2097152: 2 MB
•
4194304: 4 MB
•
8388608: 8 MB
•
16777216: 16 MB
•
33554432: 32 MB
•
-2147483648: Maximum