Physical memory versus detected memory 2.4.7-10

Physical memory versus detected memory 2.4.7-10

[ivan]

Dear list users.

My server detects less memory than it available. 

	Available memory according to the BIOS 4049MB.

	System sees only 3.7GB ???
	Mem:  3799580K av, 1606816K used, 2192764K free, 468K shrd, 376972K buff
	Swap: 8192992K av, 0K used, 8192992K free 1037532K cached


OS RedHat 2.7 standard kernel.
	Linux atlas.es.usyd.edu.au 2.4.7-10smp #1 SMP Mon Dec 10 13:08:57 EST 2001 i686 unknown

Hardware PowerEdge 4400. 
	( supports 4GB )

Additional problem:  
	random crushes, trying to to find out why.

Questions : 	1) Any comments on why top only shows 3.7 Gb are welcome.


Thank you.
================================================================================

Ivan Teliatnikov,
F05 David Edgeworth Building,
Department of Geology and Geophysics,
School of Geosciences,
University of Sydney, 2006
Australia

e-mail: ivan@es.usyd.edu.au
ph:  061-2-9351-2031 (w)
fax: 061-2-9351-0184 (w)

===============================================================================

Re: Physical memory versus detected memory 2.4.7-10

[Ken Brownfield]

Well, I don't know about that specific machine, but HP LP6000 boxes
reserve 700MB (!) for PCI hot-plug support.  So my 4GB boxes are
actually 3.3GB boxes.  Can't override it, says HP.  They wouldn't refund
70% of the price of a 1GB stick, either. ;)

I suspect what you're seeing is along the same lines; perhaps PCI
hotplug or some other reservation that may be tweakable in the PowerEdge
BIOS.  Dell may or may not be able to help.

FWIW; good luck,
-- 
Ken.
brownfld@irridia.com

On Fri, Jan 25, 2002 at 12:05:10PM +1100, ivan wrote:
| 
| Dear list users.
| 
| My server detects less memory than it available. 
| 
| 	Available memory according to the BIOS 4049MB.
| 
| 	System sees only 3.7GB ???
| 	Mem:  3799580K av, 1606816K used, 2192764K free, 468K shrd, 376972K buff
| 	Swap: 8192992K av, 0K used, 8192992K free 1037532K cached
| 
| 
| OS RedHat 2.7 standard kernel.
| 	Linux atlas.es.usyd.edu.au 2.4.7-10smp #1 SMP Mon Dec 10 13:08:57 EST 2001 i686 unknown
| 
| Hardware PowerEdge 4400. 
| 	( supports 4GB )
| 
| Additional problem:  
| 	random crushes, trying to to find out why.
| 
| Questions : 	1) Any comments on why top only shows 3.7 Gb are welcome.
| 
| 
| Thank you.
| ================================================================================
| 
| Ivan Teliatnikov,
| F05 David Edgeworth Building,
| Department of Geology and Geophysics,
| School of Geosciences,
| University of Sydney, 2006
| Australia
| 
| e-mail: ivan@es.usyd.edu.au
| ph:  061-2-9351-2031 (w)
| fax: 061-2-9351-0184 (w)
| 
| ===============================================================================
| 
| 
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| Please read the FAQ at  http://www.tux.org/lkml/

Re: Physical memory versus detected memory 2.4.7-10

[Jeff Chua]

On Fri, 25 Jan 2002, ivan wrote:
> My server detects less memory than it available.
> 	Available memory according to the BIOS 4049MB.
>
> 	System sees only 3.7GB ???
> 	Mem:  3799580K av, 1606816K used, 2192764K free, 468K shrd, 376972K buff
> 	Swap: 8192992K av, 0K used, 8192992K free 1037532K cached

I think you need to recompile the kernel to support 64GB mem.

You current config seems to support up to 4GB only (but it is a bit
less than 4GB). I had a similar problem where I had 1GB, but saw only
9xxGB.

Jeff

Re: Physical memory versus detected memory 2.4.7-10

[Jeff Chua]

On Fri, 25 Jan 2002, ivan wrote:
> My server detects less memory than it available.
>       Available memory according to the BIOS 4049MB.
>
>       System sees only 3.7GB ???
>       Mem:  3799580K av, 1606816K used, 2192764K free, 468K shrd,
376972K buff
>       Swap: 8192992K av, 0K used, 8192992K free 1037532K cached

I think you need to recompile the kernel to support 64GB mem.

You current config seems to support up to 4GB only (but it is a bit
less than 4GB). I had a similar problem where I had 1GB, but saw only
9xxGB.

Jeff

RE: Physical memory versus detected memory 2.4.7-10

[Matt_Domsch]

> | My server detects less memory than it available. 
> | 
> | 	Available memory according to the BIOS 4049MB.
> | 
> | 	System sees only 3.7GB ???
> | 	Mem:  3799580K av, 1606816K used, 2192764K free, 468K shrd, 376972K
buff
> | 	Swap: 8192992K av, 0K used, 8192992K free 1037532K cached

The difference is space assigned to PCI cards or reserved for hot-plug PCI
cards.  You should be able to run a CONFIG_HIGHMEM64G-enabled kernel (such
as the Red Hat 2.4.x-enterprise kernels instead of the -smp kernel) and be
able to use the remaining memory, at the performance cost of enabling PAE.

Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer
Dell Linux Solutions www.dell.com/linux
#1 US Linux Server provider with 24.5% (IDC Dec 2001)
#2 Worldwide Linux Server provider with 18.5% (IDC Dec 2001)