[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: how to tell what's using memory?

On Monday 18 August 2003 09:14, Michael Martinez wrote:
> We've got a RH Linux ES 2.1 server (Redhat 7.2 smp) that has 3.5 Gig
> on board memory.
> We've got minimal processes running on this thing. Usually about 3.0
> Gig RAM is free.
> however, we have an oc4j (java) application that uses up a small
> amount of memory, probably about 100Meg.
> Applications folks were stress testing this application over the
> weekend, and noticed that the application was using up memory. Then,
> they shut down the application, but the memory was not freed.
> Now we're trying to figure out why the memory was not freed. none of
> the application threads are showing up in the "ps" output, but the
> memory usage for the total system is at about 1.7Gig usage, with 1.8
> Gig free.
> We expect there should be almost 3 Gig free. So how do we find out
> what's holding the rest of the mem?

In the world of Unix, unused ram is wasted ram.  You're seeing buffering 
and caching in action.  Take a closer look at "free -m" and you'll see 
the difference line (+/- buffers/cache).  When you think about it, 
Microsoft's model of use as little physical ram as possible, and as 
much page file as possible, thus showing a huge amount of "free ram" is 
really quite silly and wastefull.  The "in use" ram of your Linux 
system will be freed as needed, but next time you run that particular 
app, it'll run much faster due to all of it's info being cached.

Jesse Keating RHCE MCSE
Mondo DevTeam (http://www.microwerks.net/~hugo/)

Was I helpful?  Let others know:

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]