Which kernel of 32 bit Redhat and Suse linux supports 128 GB physical memory in ProLiant BL460c G6.

[senthil_kumar_1]

Hi All,

We would like to install 32 bit RHEL 5.X and Suse 11.x in ProLiant BL460c G6.

This server is having 128 GB physical memory.

We are able to see 64 GB from 32 bit RHEL 5.X (PAE kernel has been installed).

And 72 GB from 32 bit SLES 11.x (default kernel has been installed).

My questions:

1)Does 32 bit Redhat and Suse linux support 128 GB physical memory?

2)Which kernel of 32 bit Redhat and Suse linux supports 128 GB of physical memory?


3)Which architecture (32 bit or 64 bit) of redhat and suse support 128 GB physical memory?

[iinfi1]

i believe 32-bit OS with PAE kernel will support only upto 64 GB memory. i dont know how SuSe supports 72GB for you. i m not sure

you will have to use 64-bit OS for the same. IMO all applications 32-bit or 64-bit will work without much hassles in a 64-bit OS. you will have use 32-bit libraries if using 32-bit apps in 64-bit OS
correct me if i am wrong

[senthil_kumar_1]

1)How much memory 64 bit Linux OS support?

2)How many processor 32 bit Linux OS support?

3)How many processor 64 bit Linux OS support?

[Suman_1978 · Accepted solution]

Senthil,

1) RHEL 5.x and SuSE 11 x86 does not support 128GB RAM.

2) None (according to my knowledge)

3) Refer to these links:
http://www.novell.com/products/server/techspecs.html
http://www.redhat.com/rhel/compare/

Workaround:
If you have installed 128GB of physical RAM, you can try this workaround.

Modify the Linux boot configuration file (grub.conf or lilo.conf) and add the following parameter to the kernel command line:

For Intel-based servers WITHOUT I/O Memory Management Unit (IOMMU) or Graphics Address Remapping Table (GART) support, add the following:

iommu=soft swiotlb=131072

Hope this command works in your server.

[iinfi1]

RHEL 5.x does support over 200GB memory in the 64-bit version.
didnt know that 32-bit from v5 only supports upto 16GB
wats the reason? any idea why they stopped providing it with the PAE kernel?
abt an year back i remember attending a rhel seminar where they were boasting abt the 32bit one supporting 64 Gigs. yes it was v5.1.
:(
me bad

[Riaan van Niekerk]

There are technical reasons for not supporting larger than 16 GB on 32-bit RHEL 5 and RHEL 6. The hugemem kernel on RHEL 4 worked around these limitation at the cost of performance and/or a clean architecture. (I got the impression that the hugemem kernel required to access 64 GB RAM on 32-bit RHEL 4 was a bit of a kludge). By the time RHEL 5 was released, 64-bit capable hardware was widely available, which negated the need for the hugemem kludge.