HP MSA 1040 HP MSA 1040 CLI Reference Guide (762782-001, March 2014) - Page 363

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 volume-name write-policy write-policynumeric cacheoptimization cacheoptimizationnumeric read-ahead-size string string string uint32 string uint32 string If a volume is specified, its serial number. If a volume is specified, its name. 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. Numeric equivalents for write-policy values. • 0: write-through • 1: write-back 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. Numeric equivalents for cache-optimization values. • 0: standard • 2: no-mirror 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. cache-parameter 363