Memcached Statistics Items Test

Memcached caching system is distributed in memory caching solution, and is used primarily to provide high speed data retrieval for web applications. An effective way to understand the performance of hte cache is to look at the statistics around the items in the cache. That is the reason it is important to monitor the items statistics, so that administrators have a clear view of performance.

This test monitors the Memcached caching system and collects key indicators around iItems statistics like number of items evicted, number of out of memory errors received etc.. These statistics help administrators get valuable insights into Memcached performance.

Target of the test : Memcached caching system

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for Memcached caching system

Configurable parameters for the test

Parameter	Description
Test period	How often should the test be executed.
Host	The IP address of the target server that is being monitored.
Port	The port number through which the Memcached communicates.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Evicted	Indicates the average number of items evicted from the cache in one second.	Evictions/Sec	A high number of evictions could be a good sign that unused data can no be replaced with more valuable data.
Evicted non zero	Indicates the average number of evicted items which have been referenced at least once.	Evictions/Sec	If the items evicted have been referenced but not referenced recently, it is okay to evict them.
Out of memory	Indicates the average number of out of memory errors received in a second	Errors/sec	A high number of out of memory exception clearly states that it is time to evict some items from the cache. If it is not happening automatically, administrators need to look at eviction criteria.
Tail repairs	Indicates the average number of times in a second, the cache tail has to be repaired.	Numbers/sec
Number of items present	Indicates the total number of items present in the cache at the moment.	Number	The number of items in the cache should be high enough but leaving memory for new items to be added.
Oldest item age	Indicates the age of oldest item.
Last evicted time	Indicates the time elapsed since last eviction.	Sec	Eviction of items from the cache should be regular process which will allow for memory to be frred.