Monitoring the Efficiency of the Caching Mechanism

Each controller in an EMC disk array can be configured to use a specified amount of memory to cache the read and/or write operations. The solution reports the amount of memory configured by each controller for the read and write operations (the ReadCacheSize and WriteCacheSize parameters are available in the infobox of the SEN_EMC_CONTROLLER_CLAR and SEN_EMC_CONTROLLER_SYMM application classes).

The WriteFlushByteRate parameter of the SEN_EMC_CONTROLLER_CLAR application class represents the rate in MB/sec at which data is committed to the disk (i.e. physically written). This value is to be compared with the WriteByteRate of the disk array.

The CacheDirtyPagesPercentage parameter represents the amount in percentage of the write cache that has been modified by host write operations and not yet flushed to the disks. Reaching 100% means that write cache is too small and cannot handle the flow of write operations.