process to use more than 2GB RAM

simplyrahul · 10-27-2004, 02:08 PM

I have a machine running ORACLE with 8 cpu's and 8GB RAM. Linux not able to use more than 2GB RAm now. Do upgrading to 2.6 kernel will help ?

Tinkster · 10-27-2004, 02:16 PM

Recompiling the current kernel with appropriate settings
should do, 2.4 can handle up to 64GB ... or are you
saying that the application can't allocate more than 2GB?

Cheers,
Tink

simplyrahul · 10-27-2004, 02:22 PM

Can u help me with recompiling the kernel to help use more than 2GB of RAM(upto 8GB).I'm currently using.

2.4.21-20.ELsmp

Thanks

Tinkster · 10-27-2004, 02:29 PM

Change into the directory with the kernel source.
Edit .config
Find CONFIG_HIGHMEM and make sure it's a)
no commented out and b) set to CONFIG_HIGHMEM=y

CONFIG_HIGHMEM64G=y
# CONFIG_HIGHMEM4G

Follow the RH recommendations for kernel recompiling.

Cheers,
Tink

simplyrahul · 10-27-2004, 02:35 PM

Thanks Tink,
Let me see if can crak that.

Thanks in advance.
Rahul

simplyrahul · 10-27-2004, 02:39 PM

Hi Tink,

Following entry already there in .config file

#CONFIG_NOHIGHMEM is not set
#CONFIG_HIGHMEM4G is not set
CONFIG_HIGHMEM64G=y

Cheers,
Rahul

Tinkster · 10-27-2004, 02:55 PM

That looks correct ... odd.

What do you get when you issue
free
?

Cheers,
Tink

simplyrahul · 10-27-2004, 02:56 PM

any idea on how to use ram more than 2GB ?

Thanks,
Rahul

Tinkster · 10-27-2004, 03:01 PM

Brings us back to my first question: who/what doesn't
use more than 2GB, the kernel or oracle? What's the
output of free?

Cheers,
Tink

simplyrahul · 10-27-2004, 03:08 PM

total used free shared buffers cached
Mem: 8207480 8187212 20268 0 287068 7551764
-/+ buffers/cache: 348380 7859100
Swap: 4194216 0 4194216

Tinkster · 10-27-2004, 03:13 PM

I'm confused ... that clearly states that it uses 8GB.

What exactly is your problem?

Cheers,
Tink

simplyrahul · 10-27-2004, 03:19 PM

Don't know how it started.
previously it wasn't crossing 2GB.
and i haven't done anything..seriously.

But anyways thanks alot for your help,

Cheers,
Rahul

jspenguin · 10-27-2004, 08:17 PM

What kind of processor is it? If it is a 32-bit processor, then *NO* process has more than 4GB total address space. Linux typically reserves the top 1GB of address space for the kernel, memory-mapped I/O, etc. If it's a 64-bit x86 processor, it could be that the program could be compiled in 32-bit mode.