eG Monitoring
 

Measures reported by HiVSPCSWSMATest

An access path is a path through which data and commands are transferred within a disk subsystem. Since data is written to the cache memory via a cache switch, the cache switch to cache memory route is also an access path. If there are too many writes still pending to the cache memory, you might want to know how the data transfer in this path is progressing to determine whether a slowdown in the path could have contributed to the high write-pending rate. The HiVSPCSWSMATest monitors the usage of each cache switch to cache memory access path to facilitate such an analysis.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Short_CSWCMA Indicates the percentage usage of this cache switch to cache memory access path. Percent A very high value or a value close to 100% for this measure could indicate that the access path is over-utilized, probably owing to a slow data write rate to the cache. Comparing the value of this measure across paths could indicate which path(s) is choking.

Data could be transferred slowly over a path if cache does not have enough space to accommodate the data. Such an event could occur if the cache is unable to write data to the disk quickly; a slowdown in writes to disk can severely hamper the cache's ability to make space for data waiting to be written, thus crowding the access path.