Even if I found lots of sites and forums where these values have been discussed, I'm still not quite sure about in meaning of Buffers and Cached. Most sites refer to these values as:

Buffers: The amount of physical RAM used for file buffers.
Cached: The amount of physical RAM used as cache memory.

What is the actual meaning of "file buffers" ? Is the the cache for "cached read IOs" ?
Means "cache memory" also cache of swapped pages ?

Can I assume if the system gets under memory space pressure it will free memory from these caches ?

I'm dealing with Oracle Databases on Linux Servers. So some of my systems have about 16-32 GB RAM.

So If I see values like these, does this mean the system has about 13GB cache which could potentially freed ?

$ free
total used free shared buffers cached
Mem: 16436916 16027568 409348 0 1147152 13692012
-/+ buffers/cache: 1188404 15248512
Swap: 20479992 128 20479864

best regards

Sorta ... as always "it depends". In the Oracle case, it depends on SGA.
Have a look at this. Explains things from an Oracle perspective.

Hi,

thanks for the reply but it seems the link is broken.

Actually I just want to understand the relevance of this parameters ( eg if the system in undersized in terms of memory )
Besides I could not find a hint about this parameters if hugepages are in use.
Oracle database usually use large amounts of shared memory. Is there a difference in regarding these parameters ?

best regards

Sorry - extraneous right parenthesis. Try it now.

You *just* want to understand memory ...
lol - when you figure it out, come tell the rest of us.

Hugepages influence (to some extent) depend on kernel level - and machine architecture. So it (still) "depends" ...
There's probably no "right" answer.

Thanks for the Link, covers lots of details ...

best regards to Australia