memory limits to es3, u4, redux

[Rick Stevens]

On Mon, 2006-06-12 at 11:48 -0700, chuck lawrence wrote:
> > Subject: Re: memory limits to es3, u4
> > From: Bob McClure Jr <bob at bobcatos.com>
> > Date: Fri, 9 Jun 2006 15:26:10 -0500
> > To: Getting started with Red Hat Linux <redhat-install-list at redhat.com>
> > 
> > On Fri, Jun 09, 2006 at 01:07:18PM -0700, Ron McKeever wrote:
> > 
> >>This might help:
> > 
> > 
> > Here is the URL pasted back together.  (#$%&#$ MS Lookout)
> > 
> > 
> >>http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/sysadmin-guide/ch-kernel.html
> 
> I'll try this, but I've got a couple of questions.  I haven't upgraded a 
> kernel manually for awhile.
> 
> 1.  shouldn't the existing kernel see at least 4gb of the 8gb?  I'm only 
> getting 3gb.

Depends on how you're looking at it.  The normal split is 1GB for the
kernel and 3GB for userspace.  "cat /proc/meminfo" should show all 4GB
and "free" may only show userspace.  I can't recall if it shows all of
it.  Unfortunately, my machines with >4GB of RAM use a customized kernel
that splits it 50-50 between kernel and userspace.

> 2.  should I try to look for a "bigmem" version that matches the version 
> # of my existing kernel?  I'm not finding "bigmem" with the right 
> version, but I do find "hugemem" (which you or someone suggested).  will 
> "hugemem" support less than 16gb?

Yes, hugemem is the right beast to use, and it should support 64GB.

> > Also an upgrade to RHES v4 would be a good idea.  You get the 2.6.xx
> > kernel.  I'm administering a couple of 2x2 Opteron boxes and it sees
> > all four CPUs.
> 
> it actually came with es4, but our application vendor doesn't support it 
> yet...  pity.

Ah, ye ol' "2.4 kernel vs. 2.6 kernel" situation.

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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-                    I doubt, therefore I might be.                  -
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