eG Monitoring
 

Measures reported by OraExaFlCaStTest

The Exadata Smart Flash Cache is a cache on the cell (storage) server for storing redo-data until this data can be safely written to disk. The Oracle Exadata storage server comes with a substantial amount of flash storage. A small amount is allocated for database logging, and the remainder is used for caching user data. Exadata Smart Flash Cache can intelligently determine the data that is most useful to cache based on data usage, access patterns, and hints from the database that indicate the type of data being accessed. The flash 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 flash cache, it is necessary to keep track on the status of the flash cache. The OraExaFlCaStTest helps administrators to keep a vigil on the cache!

This test auto-discovers the flash caches on the target storage server and for each flash cache reports the status. This test also reveals the cell disks that are allocated to each flash cache and those cell disks that are unavailable. In addition, this test also reveals the size of the flash cache that is available for use. Using this test, administrators can figure out those flash caches that are in a critical state, isolate them and fix issues proactively. Also, administrators can figure out the flash cache that is currently being most utilized.

Outputs of the test: One set of the results for each flash cache on the target Oracle Exadata Storage Server that is being monitored

Descriptor: Flash cache

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
fcStatus Indicates the current status of this flash cache.  

The table below indicates the values that this measure can report and their corresponding numeric equivalents:

Measure value Numeric Value
Normal 100
Import required 90
Critical 50

Note:

By default, this measure reports the above-mentioned Measure Values while indicating the current status of the flash cache. However, in the graph of this measure, the status of the flash cache will be represented using the corresponding numeric equivalents only.
allocatedCellDisks Indicates the number of cell disks allocated to this flash cache. Number

The detailed diagnosis of this measure lists the names of the cell disks allocated to the flash cache.
fcSize Indicates the total size of this flash cache. TB

 

usableFCSize Indicates the size of this flash cache that is available for use. TB

 

usableFCSizePct Indicates the size of this flash cache in terms of percentage, that is available for use. Percent

A value close to 0 indicates that the flash cache is running out of space.

unAvailableCellDisks Indicates the number of cell disks that are currently unavailable for this flash cache. Number