Re: Solaris "infinite" shmmax value?

The shmmax size is just a soft limit on the size of a shared memory segment, so shared memory is allocated in segments with a max size of SHAMMAX. So if the SHMMAX value is large, it means that only one segment is allocated. So if SHMMAX=128MB, and your SGA is 600MB, it will allocate 4 segments of 128MB and one of 88MB. If a SHMMAX is 800MB, and you a want a SGA of 600MB, it will allocate one segment of 600MB.

SHMALL used to limit the total amount of Shared Memory that could be allocated on the system. Obviously there are also some other limits to consider like internal memory.

Anjo.

On 8/25/06, Tanel Poder <tanel.poder.003_at_mail.ee> wrote:
>
> > In Solaris, is a shmmax setting of
> >
> > set shmsys:shminfo_shmmax=0x40000000 or
> > set shmsys:shminfo_shmmax=0x80000000
> >
> > legitimate and is it "infinite", i.e. the amount of physical
> > memory available on the server?
>
> I don't know any infinte shmmax special values, all numbers represent real
> bytes, you could just set it larger than you need.
>
> But lets start with basics:
>
> 1) which version of solaris and is it 32 or 64 bit? (in solaris 10 many
> kernel parameters have changed)
> 2) how much RAM you've got?
> 3) how big SGAs are you planning there?
>
>
> Tanel.
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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Anjo Kolk
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