Is it safe to use up all memory on linux server, not leaving anything for the cache?

Posted by Temnovit on Server Fault See other posts from Server Fault or by Temnovit
Published on 2012-09-16T11:13:27Z Indexed on 2012/09/16 15:40 UTC
Read the original article Hit count: 169

Filed under:

linux

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mysql

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centos

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memory

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cache

I have a CentOS server fully dedicated to MySQL 5.5 (with innodb tables mostly). Server has 32 GB RAM, SSD disks, and avarage memory usage looks like this:

free

So about 25GB is in use and about 6.5GB is cached. I am experiencing performance problems with WRITE queries, so I was thinking, is this the optimal cache size? I might increase innodb buffer size, so that linux cache would become smaller, or decrease it, so it would be bigger.

What is the optimal used/cached memory balance for busy MySQL server on linux?

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