HP MSA 2040 CLI Reference Guide

cache-parameter 375
cache-parameter
This basetype is used by show cache-parameters, when a volume is specified, to show volume cache
properties.
Table 12 cache-parameter properties
Name Type Description
serial-number string If a volume is specified, its serial number.
volume-name string If a volume is specified, its name.
write-policy string If a volume is specified, its cache write policy.
• 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.
write-policy-
numeric
uint32 Numeric equivalents for write-policy values.
• 0: write-through
• 1: write-back
cache-
optimization
string If a volume is specified, its cache optimization mode.
• standard: Optimizes cache for both sequential and random reads.
Appropriate for applications that read and write small files in random order,
such as transaction-based and database update applications. This is the
default.
• no-mirror: When this mode is enabled, each controller stops mirroring its
cache metadata to the partner controller. This improves write I/O response
time but at the risk of losing data during a failover. ULP behavior is not
affected, with the exception that during failover any write data in cache will
be lost.
cache-
optimization-
numeric
uint32 Numeric equivalents for cache-optimization values.
• 0: standard
• 2: no-mirror
read-ahead-size string If a volume is specified, its read-ahead cache setting.
• Disabled: Read-ahead is disabled.
• Adaptive: Adaptive read-ahead is enabled, which allows the controller to
dynamically calculate the optimum read-ahead size for the current workload.
• Stripe: Read-ahead is set to one stripe. The controllers treat non-RAID and
RAID-1 vdisks internally as if they have a stripe size of 512 KB, even though
they are not striped.
• 512 KB, 1 MB, 2 MB, 4 MB, 8 MB, 16 MB, or 32 MB: Size
selected by a user.