shmmax increase

[Javier Ortiz Guajardo]

we increase the physical memory from 3.5 Gb to 8Gb. we have a hpux 11.0 64 bits.
The shmmax value is 1073741824.

how can i tune this parameter?

[Jan Sladky]

Hi Javier,

try kmtune command.


rgds Jan

[Geoff Wild]

By either the command line or use sam.

http://docs.hp.com/en/5990-8172/ch03s09.html#cjacdbcg

Rgds...Geoff

[Steven E. Protter]

shmmax will only go up to 25% of total memory.

Memory is defined as swap plus ram. If you exceed that figure it will be ignored by the system.

SEP

[Hoang Chi Cong_1]

Hi

Please refer to this thread:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=773637

Anyway, when tune this parameter, it depend on the application is running on your system...
To tune it just do:
+kmtune -s shmmax=
+/usr/lbin/sysadmin/system_prep -s system
+mk_kernel -s system
+kmpudate

And then copy /stand/vmunux to vumunix.bak

Then copy the new one to vmunux

shutdown -ry

Hope this helps
HoangChiCong

[Hoang Chi Cong_1]

And here is good for you about shmmax kernel parameter:
http://docs.hp.com/en/B2355-60105/shmmax.5.html

Regard,
HoangChiCong

[MAUCCI_2]

Steven,

are you sure of what you said?
AFAIK, shmmax is just a barrier to prevent somebody from eating up all memory.
It can be set far above total memory on the system.


++Cyrille

# kmtune -u -s shmmax=0xFFFFFFFFF
The kernel's value of shmmax has been set to 68719476735 (0xfffffffff).
# swapinfo -mt
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4096 0 4096 0% 0 - 1 /dev/vg00/lvol2
reserve - 4096 -4096
memory 6666 5812 854 87%
total 10762 9908 854 92% - 0 -
# kmtune | grep shmmax
shmmax 0xfffffffff Y 0xFFFFFFFFF