Used RAM

[Cathal]

Hello everyone,

I have wondered why FreeNAS / FreeBSD uses all RAM available. Today I have two servers running with 64 and 16 Gb RAM, and all RAM is used.

Are there any with a good explanation of it?

 

[rvassar]

Yes. Any RAM not needed by the kernel & running processes is consumed by the ZFS ARC. Basically a cache to make things faster.

 

[Chris Moore]

Are there any with a good explanation of it?

It is a basic function of the file system, as implemented in FreeNAS, that ZFS (the file system) uses available RAM for ARC (Adaptive Replacement Cache) and this has been discussed many times on the forum. It is the reason we generally guide people to have more memory as it can improve performance.

My question to you is, why are you asking? Are you having some problem?

While you are answering, please also read the forum rules and provide the requested information about your system or systems

Updated Forum Rules 12/5/18
https://forums.freenas.org/index.php?threads/updated-forum-rules-12-5-18.45124/

 

[Kevin Horton]

Hello everyone,

I have wondered why FreeNAS / FreeBSD uses all RAM available. Today I have two servers running with 64 and 16 Gb RAM, and all RAM is used.

Are there any with a good explanation of it?

You paid for the RAM. Why should FreeNAS not use it?

FreeNAS will use all available RAM to keep various things in cache to speed up access, if that data is needed again. Caches get flushed if the RAM is needed for something more critical.

FreeNAS using all available RAM is a feature, not a bug.