Large memory issues

David Landgren david at
Wed Aug 27 10:26:37 PDT 2003

Irvine Short wrote:

> Hey All
> and it was slightly better - managed to boot halfway with everything
> running out of memory.
> I then found that this:
> options         MAXDSIZ="(2048*1024*1024)"
> options         MAXSSIZ="(128*1024*1024)" (and also 64MB)
> options         DFLDSIZ="(512*1024*1024)"
> worked fine but not as expected - limit reports datasize unlimited.

I've managed to crank it up as far as

options MAXDSIZ="(3568*1024*1024)"

This is for a squid proxy. Right now I have

% ps uUnobody
nobody   132  0.0 55.6 2185016 2184992  ??  S    18Aug03  43:08.02 
squid -NsY
nobody   133  0.0  0.0   864  412  ??  Ss   18Aug03   0:28.88 
(unlinkd) (unlinkd)

which is pretty sweet. Which reminds me, I have to tweak my squid conf 
a bit to let it blow another gig or so of RAM :)

> I'd kind of like a default of 512MB with the option to loosen it.
> Any offers as to what's the proper way to do this? All's well at the mo
> but it doesn't seem right.

man limits

> Configging MAXDSIZ to 3500*1024*1024 did the same as 4095
> Also, when the machine boots it says:
> CPU: Intel(R) Xeon(TM) CPU 2.40GHz (2392.25-MHz 686-class CPU)
>   Origin = "GenuineIntel"  Id = 0xf27  Stepping = 7
>   Hyperthreading: 2 logical CPUs
> real memory  = 4025942016 (3931584K bytes)
> and then later it says on the console something like:
> 256MB of RAM over 4GB ignored.
> Seems silly to waste 256MB RAM so any hints would be appreciated here
> too.

How can you address more than 2^32 bytes of RAM with a 32 bit 
processor? :)

Intel have invented a kluge called PAE (Page Address Extensions which 
lets you eke a bit more out of the current Pentium architecture -- but 
single processes are still limited to a 4Gb address space. And the 
talk a while back on freebsd-current was that it has a slight 
performance impact as well.


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