VSP Cache Status Test

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 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.

Target of the test : A Hitachi VSP storage device

Agent deploying the test : An external agent

Outputs of the test : One set of results for every RAID store on the Hitachi VSP device monitored

The figure below depicts the test configuration page of this test. Click on the parameters in the figure below to know what they are and how to configure them.

Measures made by the test:
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 - 1 to 5.