eG Monitoring
 

Measures reported by HiVSPGxCacheStTest

The Hitachi VSP(Virtual Storage Platform) places all read and write data in the cache. The amount of fast-write data in cache is dynamically managed by the cache control algorithms to provide the optimum amount of read and write cache, depending on the workload read and write I/O characteristics. The Hitachi VSP is designed so that it cannot lose data or configuration information from the cache if the power fails. The cache is protected from data loss up for up to ten minutes by the cache destage batteries while the data is copied to the cache SSD (flash memory) on the cache boards. The cache may lose data due to reasons such as frequent power failure, corruption of the cache, memory overflow of the cache etc. To avoid such loss of data from the cache, it is necessary to keep track on the status of the cache and if errors are detected, administrators should identify the criticality of such errors! The VSP Gx00 Cache Status test helps administrators to keep a vigil on the cache!

This test reports whether the cache used by each RAID store on the storage device is currently experiencing any errors, and if so, how critical the error is.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Cache_status Indicates the current status of the cache used by this RAID store.   The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure value Numeric Value
noError 1
acuteError 2
seriousError 3
moderateError 4
serviceError 5

Note:

By default, this measure reports the Measure Values listed in the table above to indicate the current state of the cache used by this RAID store. The graph of this measure however, represents the status of a server using the numeric equivalents only i.e., 1 to 5.