something like sar for memory?

Daniel Carrillo daniel.carrillo at gmail.com
Tue Jun 30 12:15:48 UTC 2009


2009/6/30 ESGLinux <esggrupos at gmail.com>:
> Well,
> Now I get the info with sar comes the problem to understand the results.
>
> Allways I try to see the real used memory in linux I have the same problem,
> it seems that it´s using ALL the memory.
>
> with sar -r:
>                kbmemfree kbmemused  %memused kbbuffers  kbcached kbswpfree
> kbswpused  %swpused  kbswpcad
> 12:55:01       408540   3740728              90,15    391560   1191012
> 4096200       332           0,01                 48
>
> my system has 4GB and it looks it has 3,7G in use, but I don´t think it´s
> true.
>
> with the free -m command:
>
> free -m
>                   total       used       free     shared    buffers
> cached
> Mem:          4052       3705        346          0        384       1217
> -/+ buffers/cache:       2103       1948
> Swap:         4000          0       4000
>
> the result is the same, but I have heard that the real free memory is the
>  in the colum free in the -/+ buffers/cache, is it true?
>
> with vmstat as Manuel suggests:
>
>  vmstat -s -S m
>         4248 m total memory
>         3907 m used memory
>         2992 m active memory
>          738 m inactive memory
>          341 m free memory
>          404 m buffer memory
>         1289 m swap cache
>         4194 m total swap
>            0 m used swap
>         4194 m free swap
>    ....
>
> what is command I get other results
>
> so how many memory are free on my system :-( ?
>

Usually, all the commands take the information from:

/proc/meminfo (you can 'cat' it)

I suggest the read of
http://virtualthreads.blogspot.com/2006/02/understanding-memory-usage-on-linux.html

Hope this helps.




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