How to reduce RAM on a Sun Enterprise 250 Server?

How to reduce RAM on a Sun Enterprise 250 Server?

Post by webs.. » Tue, 08 Jun 1999 04:00:00



Hi all,

We recently bought a Sun E250 Server and it has about 2 Gig ram. For
performance evaluation purposes, I need to reduce the ram to half (1
Gig) and run our internal bench mark tests. Can any one suggest me how
to physically remove ram from the Server and put it back? Is there any
other option? Also, how much swap space should I allocate? Right now
this machine has about 256MB swap, but I dont think its being used.

Thanks a lot for your input
Kris--

 
 
 

How to reduce RAM on a Sun Enterprise 250 Server?

Post by Noel Hayd » Wed, 09 Jun 1999 04:00:00


In the 250 the simms go in in quads.  Take out the 8 simms furthest from
the pci banks. (banks c & d)

Noel

 
 
 

How to reduce RAM on a Sun Enterprise 250 Server?

Post by Joe Bottom » Fri, 11 Jun 1999 04:00:00


IIRC you can reset physmem to a artificially lower amount
of memory than is actually on the host... Sorry that I can't
remember how it is done... any performance/benchmarker experts
out there???

> Hi all,

> We recently bought a Sun E250 Server and it has about 2 Gig ram. For
> performance evaluation purposes, I need to reduce the ram to half (1
> Gig) and run our internal bench mark tests. Can any one suggest me how
> to physically remove ram from the Server and put it back? Is there any
> other option? Also, how much swap space should I allocate? Right now
> this machine has about 256MB swap, but I dont think its being used.

> Thanks a lot for your input
> Kris--

 
 
 

How to reduce RAM on a Sun Enterprise 250 Server?

Post by Mike Minamot » Fri, 11 Jun 1999 04:00:00


You can do this in /etc/system

set physmem=XXXXX

XXXXX is number of pages.  Depending on architecture involved
this can be 4 or 8K...

Check your new settings with adb (man for the specifics)

adb -k /dev/ksyms /dev/mem
physmem/D

Be warned that doing this can cause the system to behave badly since
many other kernel variables depend on physmem.


> IIRC you can reset physmem to a artificially lower amount
> of memory than is actually on the host... Sorry that I can't
> remember how it is done... any performance/benchmarker experts
> out there???


> > Hi all,

> > We recently bought a Sun E250 Server and it has about 2 Gig ram. For
> > performance evaluation purposes, I need to reduce the ram to half (1
> > Gig) and run our internal bench mark tests. Can any one suggest me how
> > to physically remove ram from the Server and put it back? Is there any
> > other option? Also, how much swap space should I allocate? Right now
> > this machine has about 256MB swap, but I dont think its being used.

> > Thanks a lot for your input
> > Kris--

--
Mike Minamoto
Science Applications International Corporation
10260 Campus Point Drive (MSE-2)
San Diego, CA 92121
858.826.9414 / 305.675.8410 (FAX)
888.751.4199 (Pager)