Re: 8i/Semaphore/Memory/Linux

It's not obvious, but SHMMAX is the "max seg size" entry, which is 32 megs. The 16 gig limit is the SHMMNI*SHMMAX. So, SHMMAX needs to be bumped up. It says to use half of RAM, but on a machine with a lot of RAM (more than a gig), you could go further.

Andy Johnson

In article <gfGh5.70928$i5.1131296_at_news1.frmt1.sfba.home.com>,   Will Clements <whc2u_at_leptonics.com> wrote:
> Hi ALL,
>
> Trying to get an idea of what the Linux kernel configuration
> parameters should be for a medium sized implementation of
> Oracle 8i. I've already installed Oracle 8.1.6 EE for linux
> on the stock RedHat 6.2 a few times with no problems.
>
> The Oracle documentations recommends:
>
> SHMMAX (0.5*physical memory)
> SHMMIN 1
> SHMMNI 100
> SHMSEG 10
> SEMMSL (10 + largest process parameter)
> (Default process pramaeter = 50)
> SEMMNS (set formula)
> SEMOPM 100
> SEMVMX 32767
>
> Stock RedHat 6.2 (result of "ipcs -l" command):
>
> ------ Shared Memory Limits --------
> max number of segments = 128
> max seg size (kbytes) = 32768
> max total shared memory (kbytes) = 16777216
> min seg size (bytes) = 1
>
> ------ Semaphore Limits --------
> max number of arrays = 128
> max semaphores per array = 250
> max semaphores system wide = 32000
> max ops per semop call = 32
> semaphore max value = 32767
>
> ------ Messages: Limits --------
> max queues system wide = 128
> max size of message (bytes) = 4056
> default max size of queue (bytes) = 16384
>
> My interpretation of the RedHat defaults:
>
> SHMMAX 16,777,216 KB
> SHMMIN 1
> SHMMNI 128
> SHMSEG 128
> SEMMSL 250
> SEMMNS 320000 (SEMMNI*SEMMSL)
> SEMOPM 32
> SEMVMX 32767
>
> Now according to this, really, the only thing I need to
> change is SEMOPM. Is this correct? But I'm wondering if
> I will encounter trouble if SEMMNS and SHMMAX are set
> this high. Any thoughts on this before I recompile the
> Linux kernel? (I'm also switching to kernel version 2.2.16).
>
> Will Cl
>

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