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shmmax format

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ronlevyca
Frequent Advisor

shmmax format


I am installing Oracle on an HP-UX 11.31 Itanium machine and I am required to set 'shmmax' to the size of the machine's physical memory.

What I don't know how to do is properly translate the 98gb of physical memory that my machine has into the desired number of bytes that 'shmmax' uses. I don't know if it uses gb that are 1024 mb, or 1000 mb, or various similar things down the pike. How can I correctly translate this? Or is there a command which will give me the physical memory size in honest bytes suitable for usage in 'shmmax' as opposed to something like

/usr/contrib/bin/machinfo | grep -i Memory

or

dmesg | awk '/Physical/ { print "RAM Size = "$2/1024" "MB }'

or

/usr/sbin/dmesg | grep "Physical:"

which at least gives it in Kbytes but still, the translation to proper format for 'shmmax' is unknown.

Thanks,
-Ron Levy
maybe I should just take the value for 1gb and multiply by 98.
4 REPLIES
Don Morris_1
Honored Contributor
Solution

Re: shmmax format

kctune shmmax=96Gb

[And 1Gb is 1024 Mb, yes...]

See `man 1M kctune` under the section on "Expressions" for what you can specify and what the arguments mean.
Don Morris_1
Honored Contributor

Re: shmmax format

Make that 98Gb, don't know why I read 96 initially... anyway, you get the point.
Dennis Handly
Acclaimed Contributor

Re: shmmax format

>Don: don't know why I read 96 initially.

Because you know the kernel is grabby and wants that 2 Gb for itself? :-)
ronlevyca
Frequent Advisor

Re: shmmax format

Thanks much! I was using 'smh'. That'll learn me.