topic Re: redht 7.2 increase shared memory in Operating System - Linux

redht 7.2 increase shared memory

steven Burgess_2 — Tue, 09 Mar 2004 05:27:46 GMT

Hi Everyone

I'm in an education class and need a quick answer. Were using tuxedo 6.2 with redhat 7.2. I need to double the shared memory parmaters within my kernel.

Whats the quickest way to do this

Thanks in advance

Steve

Re: redht 7.2 increase shared memory

Jerome Henry — Tue, 09 Mar 2004 05:37:01 GMT

The size of the shared memory segment is controlled by the kernel
parameters shmmax and shmall, it can be changed while the system is running
with a command like

echo "67108864" >/proc/sys/kernel/shmmax
echo "67108864" >/proc/sys/kernel/shmall
Increasing the size of the Linux shared memory segment

hth

J

Re: redht 7.2 increase shared memory

Jerome Henry — Tue, 09 Mar 2004 05:37:50 GMT

BTW, you're on kernel 2.4.x, aren't you ? Otherwise, you need to recompile if your kernel is 2.2.x...

J

Re: redht 7.2 increase shared memory

Mark Grant — Tue, 09 Mar 2004 05:38:55 GMT

Put large numbers in these files

/proc/sys/kernel/shmall
/proc/sys/kernel/shmmax
/proc/sys/kernel/shmmni

Re: redht 7.2 increase shared memory

steven Burgess_2 — Tue, 09 Mar 2004 07:34:27 GMT

Thanks Guys

Checking kernel type

Steve

Re: redht 7.2 increase shared memory

steven Burgess_2 — Tue, 09 Mar 2004 07:55:51 GMT

Cheers Guys

The penny dropped !

/etc/sysctl.conf

Add new value

kernel.shmax=

Then

sysctl -p

Where are the system default values held though ?

Cheers

Ste

Re: redht 7.2 increase shared memory

Jerome Henry — Tue, 09 Mar 2004 08:55:57 GMT

Apart from /proc/sys/kernel, check /usr/src/linux/include/asm/shmparam.h and brothers...

hth

J

Re: redht 7.2 increase shared memory

Jerome Henry — Tue, 09 Mar 2004 09:08:18 GMT

Some more details about this file structure :
http://ps-ax.com/shared-mem.html

Pls 0 here (should have precised this in former post)

J

Re: redht 7.2 increase shared memory

Stuart Browne — Tue, 09 Mar 2004 23:29:42 GMT

The system defaults are in the kernel source.

The 'echo' commands that were given are the equivalent of using the sysctl, only one has a neater interface ;)

'sysctl' (if you wade through the man page) just allows a config-file-based interface to the '/proc/sys/' structure. Replace /'s with .'s, and you've got your paths.

unf. ;)