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Old 10-27-2004, 02:08 PM   #1
simplyrahul
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Post process to use more than 2GB RAM


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 ?
 
Old 10-27-2004, 02:16 PM   #2
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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
 
Old 10-27-2004, 02:22 PM   #3
simplyrahul
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How to recompile the kernel for this ?

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
 
Old 10-27-2004, 02:29 PM   #4
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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
 
Old 10-27-2004, 02:35 PM   #5
simplyrahul
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Thanks Tink,
Let me see if can crak that.

Thanks in advance.
Rahul
 
Old 10-27-2004, 02:39 PM   #6
simplyrahul
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Hi Tink,

Following entry already there in .config file

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

Cheers,
Rahul
 
Old 10-27-2004, 02:55 PM   #7
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That looks correct ... odd.

What do you get when you issue
free
?



Cheers,
Tink
 
Old 10-27-2004, 02:56 PM   #8
simplyrahul
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any idea on how to use ram more than 2GB ?

Thanks,
Rahul
 
Old 10-27-2004, 03:01 PM   #9
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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
 
Old 10-27-2004, 03:08 PM   #10
simplyrahul
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total used free shared buffers cached
Mem: 8207480 8187212 20268 0 287068 7551764
-/+ buffers/cache: 348380 7859100
Swap: 4194216 0 4194216
 
Old 10-27-2004, 03:13 PM   #11
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I'm confused ... that clearly states that it uses 8GB.

What exactly is your problem?



Cheers,
Tink
 
Old 10-27-2004, 03:19 PM   #12
simplyrahul
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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
 
Old 10-27-2004, 08:17 PM   #13
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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.
 
  


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