CODEWITHSUNDEEP
memcacheddynatrace
Rohit Upadhyay
Rohit Upadhyay

Reputation: 1

Memcached Eviction Rate Performance

We are monitoring Memcached servers using the Dynatrace tool, the Memcached is mainly used to store user sessions related data.

We have recently increased the Memcached memory (from 1 GB to 2 GB) when we had user sessions related issues where users could not Sign In.

We thus increased the Memcached memory for 1 GB to 2 GB. Post increasing we observed a decrease in Eviction rate in the Monitoring tool (Dynatrace)

(There were NO other server/JVM related issues)

My Question: Can I co-relate the User sessions with the Eviction rate? Are there any other parameter/metric that I should look in for Memcached? Is the eviction rate normal 200/s to 400/s normal?

Here is the snap of the Eviction rate and Max bytes for last 72 hours Eviction Rate and Max_bytes

Upvotes: 0

Views: 482

Answers (1)

rmunge
rmunge

Reputation: 4228

When Dynatrace detects a problem with your user sessions it will also automatically check for anomalies in related metrics.

It is impossible to give a general recommendation on a "good" eviction rate. Focus on the user sessions and the user experience. As long as user experience is OK i wouldn't care about the eviction rate. If you should see problems with user sessions and Dynatrace should also report a relation to anomalies of the eviction rate metric, i can recommend you this article. It explains an interesting relation between the size of objects that are stored in memcached and unexpected evictions.

Upvotes: 1

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