kernel parameters

[Troyan Krastev]

Hi all,

I have to install IBM MQ Series on two of my boxes. I installation guide I see SEMMNU=2048. That works for HP-UX10.20, but when I try to change it for HP-UX11 it give me the message:
Error: One or more tunable parameters violates an interdependency rule. SAM expects the following expression(s) to be true: semmnu <= (nproc-4)
Can I avoid limitation of the formula for this parameter?
Applied Kernel Parameter Set is General OLTP/Database Server System.

Thanks,
Troy.

[Joseph C. Denman]

Not sure if you can. However, I would not suggest trying. I would up the nproc parm to 4 more then semmnu.

...jcd...

[Thierry Poels_1 · Accepted solution]

hi,
I agree with Joseph : increase you nproc parameter first.
BTW nproc < 2000 is rather low for a database server.
regards,
Thierry.

[Praveen Bezawada]

Hi
I think you can override the formula limitation if you set it from command line( i am not 100% sure ) though I suggest you not to.
Anyway the commands for changing the values from command line are

kmtune -s semmnu=2048
mk_kernel -v -o /stand/vmunix

Then reboot the machine.

Hope this helps...

...BPK...

[Troyan Krastev]

Hi Thierry,

Some calculations:
semmnu=nproc-4
nproc=(((10*MAXUSERS)/3)+128)
If I want semmnu=2048 then MAXUSERS=574, but when I try to change MAXUSERS I get:
The parameter modification(s) you have made have resulted in at least
one parameter evaluating to a value which is greater than its maximum
allowable value. Parameter "msgseg", currently set to "(MSGTQL*4)",
has evaluated to "71440", which is greater than its maximum allowable
value of "32767".

[nancy rippey]

I am running MQSeries on two HP servers running 11.0. The kernel parameters are set as follows and things are working just fine.
STRMSGSZ 65535
max_thread_proc 256
maxfiles 2048
maxfiles_lim 2048
maxswapchunks 700
maxuprc 300
maxusers 300
msgmax 65536
msgmnb 65536
msgmni 350
msgseg 7168
msgssz 1024
msgtql 1024
ncallout 3000
nkthread 2048
nstrpty 60
o_sync_is_o_dsync 1
semaem 32767
semmni 4980
semmns 16384
semmnu 2048
semume 256
semvmx 65535
shmmni 1024
shmseg 1024

[nancy rippey]

Use the semaphone settings I sent earlier. Change semmns semmni first and then you will be able to go 2048 on semmnu

[Magdi KAMAL]

Hi Troy.,

1. You may increase your nproc to a greator value ( 2068 for example ).

OR

2. You may modify the formula :
semmnu <= (nproc-4)
by
semmnu <= (nproc-4 + 1500)


Magdi

[Troyan Krastev]

Hi Maqdi,

:-), this is exactly what I am trying to do! How to do it?

[Thierry Poels_1]

hi,
increasing MAXUSERS has an effect on serveral kernel settings which might or might not be relevant for your system.
Personally I would increase nproc (fix number instead of formula) and semmnu.
(next to kmtune you can always use sam to modify the kernel parameters.)

good luck,
Thierry.

[Magdi KAMAL]

Hi again Troy.,

A)

1. sam->Kernel Configuration->Configurable Parameters
2. Select the nproc entry from the list.
Menu Actions->Modify Configurable Parameters...
3. Modify the value of Formula/value
and OK.

Say OK for new kernel generation and the system will reboot after that.

After booting you will have the new value taken into account by the kernel and you can check it by the following command :

#sysdef ? more

Magdi

[Troyan Krastev]

Hi all,

Thanks for you time! I managed to change this parameter. I applied General OLTP/Database Monolithic System Kernel Parameter set and it allowed me to set maxusers=580 and this automatically set semmnu=2057. This helped me to do what I really wanted, but the question ?CAN I AVOD LIMITATION OF THE FORMULA- is still without answer.

Thanks again,
Troy.