Memory Carnivore

R. David Whitlock ryandav at u.washington.edu
Thu Mar 29 13:15:38 PST 2001


Linux handles memory differently from Windows, at least partially because
not all changes are written to disk immediately and are instead stored to
the running memory. This is why it is evil/bad/wrong to just power off a
linux box without shutting down properly (you can force memory changes to
disk using "update").

The memory reported "free" is misleading because it doesn't include the
"buffer" total. Basically, it's much faster to make changes to memory
than write to disk, so the buffered memory is just the free space in
memory that is available for immediate use. The kernel handles these
details on its own.

In linux, what you should check is if you are using more than a teeny bit
of swap space, because the swap space is what you'll use when you're
really out of memory.

-David

"What you hear isn't necessarily what was said,
what you read isn't necessarily what was written."
-Dostoevsky

On Thu, 29 Mar 2001, WebMasterP wrote:


> Hi,

> I'm using Mandrake 7.2

> System Specs:

> Dual Celeron 550 MHz

> 640 MB of SDRAM CAS2 (256+256+128) (It's Corsair, so it's good stuff)

> DLink 530TX+

> 12GB Quantum Fireball CR (5400 RPM, ATA/66)

>

> Ok, here's what my server's doing:

> -I'm running 2 Counter Strike Servers (don't take advantage of SMP well, not

> too important though)

> -I'm hosting a forum, the forum uses sendmail so I have that daemon running

> -The forum uses perl as well, so I have that setup

> -I'm also hosting 2 stat pages for 2 of the servers (These pages aren't

> extremely popular, 100 pages displayed a day, IF THAT)

>

> Now, here's my problem

> when I check my free memory (with either 'top' or 'free') it says I have

> between 150MB and 3MB left (90% of the time it's closer to 3MB) What is

> wrong!!!!!

>

> I have everything else shut down! I shutdown xfs (X Font Server), gpm (Mouse

> Server), PHP is shutdown, any pretty much EVERY service I'm not using.

> Also, I'm still using 2.2.14-17 (mdk-secure) because I can't get 2.4.2 to

> work right ;(, but I'll deal with that later.

>

> Any suggestions?

>

> Regards,

> WebMasterP

> http://www.xtremetek.com

>

>




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