[Beowulf] confused about high values of "used" memory under "top" even without running jobs

[Joshua Baker-LePain]

On Wed, 12 Aug 2009 at 1:55pm, Rahul Nabar wrote

> Mem:  16508824k total,  7148804k used,  9360020k free,   307040k buffers
> Swap:  8385920k total,        0k used,  8385920k free,  6380236k cached
> ###########################################################
>
> On the other hand, I recall reading somewhere before that due to the
> paging mechanism
> Linux is also supposed to start using as much memory as you give it? Just
> confused if this is something I need to worry about or not.

Yes, Linux caches as much in memory as it can, and this is a good thing. 
But that memory gets released when it's needed by an active process.  So, 
above, you have 7148804k used, but the vast majority (6380236k), is cache. 
If you use 'free', it'll show you the amount not counting buffers+cache.

In short -- situation normal, nothing to see here, move along.

-- 
Joshua Baker-LePain
QB3 Shared Cluster Sysadmin
UCSF