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Max Kernel.SHMMAX in SUSE10(32Bit) ?

Link to this post 12 Feb 11

Hi All B) ,

I am working on SUSE10(32 bit). I am trying to increase my kernel.shmmax. Max i am able to set is only 4GB. Even I set more than 4GB the system doesnt accept it !!! Is the maximum SHMMAX we can set is 4GB ? or Do we have any other way to set ?

I tried the follwing steps.

vi /etc/sysctl.conf

kernel.shmmax=8589934591( Edited to 8 GB )

/sbin/sysctl -p ( to reflect the changes in SHMMAX)

cat /proc/sys/kernel/shmmax

4294967295 ( still it shows 4GB ) :(

can any one support me on this ?

Thanks in Advance

Arun

Link to this post 12 Feb 11

Since you have a 32-bit system, 4GB is the maximum value you can set...

Link to this post 13 Feb 11

I think Pavol is correct in this case, to enable a 32-bit distro to see beyond 4GB of RAM you need to verify that your kernel has HIGHMEM set, your CPU supports PAE and that your motherboard/BIOS is configured to support PAE.

You can verify you kernel settings by running the command "less /proc/config.gz|grep -i highmem"
To verify if you mobo and cpu support PAE you can check the output of "dmidecode -t bios" and "dmidecode -t processor".

Most modern distros ship their kernels with HIGHMEM4G on, but in most cases the non-server 32-bit motherboards and bios do not support PAE.

Link to this post 13 Feb 11


Max i am able to set is only 4GB

i thought that that 4 would be
4 gig - ( minus) 1 bit

and with the pae installed 4gig-1 is the MAX that 32 bit can use

have you talked to your novell rep seeing as you need to be paying them for support for SELS or SELD 10
or is this OpenSUSE10 ( opensuse 11.2 and 3 are supported )

Link to this post 14 Feb 11

HIGHMEM is the way to go,
I did it in the past with a HP server (DL180 I guess), 6Gb installed on it and a 32bit system (in that period, I'm now using only 64bit systems on real servers with Linux). I've compiled my own kernel for it, HP systems already have PAE, don't know about your current machine (manufacturer/model ?)

Link to this post 15 Feb 11

Hi Arun, you can't allow more than 4 GB in a 32 bits system. the Max is 4GB, from which 3.4 GB are just for the use and the other 600mb is for system allocation. This is not a configuration problem is a hardware problem, if you want to use more than 4GB change your processor to a 64 bits and use a 64bits Linux Version... hope this can help you

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