custom limits for kernel parameters

[Vijayakrishna]

Hi,
Does anybody have any experience with setting higher values for kernel parameters than HP recommended? It seems we can change these limits in /usr/conf/master.d/core-hpux file. I want set msgseg more than 32767 (Max by HP), Will this be a problem?
Please share any experience with this.
Thank you
Vijay

[Tom Geudens]

Hi,
We had to do something similar when installing Websphere Application Server :
root/sv00247#vi /usr/conf/master.d/core-hpux
*range maxfiles<=60000
*range maxfiles_lim<=60000
root/sv00247#shutdown ???r ???y 0

The reboot is necessary, otherwise it won't work. As to "should I do this" we got the following reply from IBM : "You either choose support from HP or support from IBM !".

Personally I would not do it, unless you get HP to confirm that the change is supported.

Regards,
Tom

[Paula J Frazer-Campbell]

Hi

The max / min kernel params are more often that not what HP ???feels??? comfortable with.

These are not guessed at but are derived for testing.

Whilst it is unlikely that your server will fall over if you exceed these setting, HP will happily support what they know and so if you change a parameter over what HP recommends and you have problems the most likely the first thing they will request is that the parameter is changed to within HP recommendations.

Speak to HP in reference to your support first.

Paula

[Helen French]

Hi Vijay:

Personally, I would not do this without consulting with HP support. Evenif you increase the parameter above the maximum limit given by HP, there will be restrictions/limitation to the new value depend up on your OS versions, resources and system properties. For safe side these points might be useful:

1) Create make_tape_recovery tapes
2) Full backup of the system
3) Backup of /stand/vmunix and /stand/system files.
4) Print out of current kernel parameters values (with SAM or sysdef or kmtune)
5) Check the impact of other kernel parameters if you increase one(in your case, the msgseg is directly related to msgssz too)
6) Check this document, this describes the similar situation (TKB #UEMSKBRC00006980):

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=c7056b610546b054e7/screen=ckiDisplayDocument?docId=200000058669704

my 2 cents ..
Shiju