[Tfug] Memory usage question

[Jeff Breadner]

On 04/02/2010 08:36 AM, earljviolet at deserthowler.com wrote:
> I run Ubuntu 9.10.  I have 1GB memory installed.
>
> When using System Monitor I show about 218 MB memory used.
>
> When I run free from the terminal I get the following results:
>               total       used       free     shared    buffers     cached
> Mem:       1009560     805740     203820          0     137416     437904
> -/+ buffers/cache:     230420     779140
> Swap:      2389020          0    2389020
>
> Is the difference in used memory between the two results because System
> Monitor shows only the 'active' memory whereas free shows everything in
> memory?
>
> Earl
>    

Linux likes to cache disk to RAM; your 218MB usage is the "active" 
application memory, add to that the buffers & cached numbers and you 
come pretty close to the used number, above.

As your applications consume more RAM, Linux will cache less data.  You 
only have to worry about memory usage once the swap space starts climbing.

cheers
   Jeff