Mysql server(ubuntu) ram usage go high after reboot. Having swap after reboot 2 days later

Question

I have a Mysql server on VM with

16 cores CPU

59 GB RAM

Ubuntu 13.10

Mysql version is 5.5.37

This is a Slave db for reporting purpose only.

Because original Mysql innodb_buffer_pool_size(49G) is so big that the server use SWAP. So I set the innodb_buffer_pool_size to 35G then restarting the server(10/12). However, the RAM usage gradually get high, almost 90% of physical RAM after two days. I think it is no reasonable since innodb_buffer_pool_size is 35G and other Mysql operation will not use so many RAM.

I am worried about db performance if the server having swap. But I do not know how to stop the Mysql ram usage. I can not see why it gradually use so many RAM.

The server start having swap after second reboot(11/28) serveral days later

Could somebody give me some hint for make sure mysql server not gradually having high RAM usage? Or is there something I need to consider. Is the ubuntu have some setting which will cause RAM consumption?

Many Thanks.

RAM USAGE

Mysql config:

https://gist.github.com/crokobit/7c329e48dc5ab234c0b1812248ff77cf

Answer 1

Comment out these lines from your my.cnf:

sort-buffer-size = 4M read-buffer-size = 2M read-rnd-buffer-size = 2M join-buffer-size = 4M 

Set buffer pool as high as 50G if it's a dedicated mysql server, check for NUMA settings and configure accordingly.

Change system swappiness to 1 (if you are using a newer kernel)

Upgrade to latest mysql versions, yours might be affected by some memory leak bug.

Answer 2

There is no magic 'use less RAM switch' so the usual sysadminly things apply understand what is happening and take appropriate action. Scientific method is your friend

• Install monitoring
• Gather data (from monitoring and other tools)
• Analyse data
• Make changes based on analysis
• Monitor effect of changes
• Rinse and repeat as required
• Document what eventually worked.

If you can't manage that yourself then hire a professional (DBA/Sysadmin) who will probably end up being cheaper than you trying to do it yourself anyway\