Instability issues on 32 bit machines with 16-48 GB of memory

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Environment

SUSE Linux Enterprise Server 10 (All Service Packs)

SUSE Linux Enterprise Server 9 (All Service Packs)

Situation

Only on x86 (32-bit) architecture:
On 32 bit machines with 16 to 48 GB of memory, the paging structure can take up enough low memory addresses to cause the kernel to run out of memory. This can cause server instability.
These issues are machine dependent and do not happen on all machines.

Resolution

Pass an option mem= to the kernel at boot time to resolve this. For example, in the GRUB configuration file /boot/grub/menu.lst, add mem=16G to the kernel line for the system to only use 16 GB of memory.

Additional Information

32-bit Servers with over 4G of memory will require the bigsmp kernel.
32-bit XEN Hosts with over 4G or memory will require the xenpae kernel.

Machines with more than 48GB of memory on 32-bit SLES systems are not supported at all. On such memory scenarios we strongly recommend to use x86_64 hardware with 64-bit SLES and run the x86 applications on it.

Please also have a look at the SLES10 SP1 release notes

Disclaimer

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