Kernel Params to be set for SAP not found on HP-UX IA 11.23

[Thierry Doppler]

Hi,

After a GoingLiveCheck, SAP recommand to control and set the following parameters on my rx2620 IA running HP-UX 11.23, but I don't find them.
- maxusers and maxswapchunks
- nbuf and bufpages (I have to set them to 0)

> man nbuf/bufpages that these parameters are obsoleted and how to set 2 others parameters;
> man maxusers say that this parameter is obsoleted, but dont't give any other new parameter to set !
> i dont't found any manpages for maxswapchunks

It's reallynot possible to control/unset nbuf/bufpages ?
Can you help me to set maxusers and maxswapchunks ?
Where can I find informations ?

Thank you for your help

Thierry

[Arunvijai_4]

You can use SAM to tune the kernel and set these parameters. Check this doc for more information http://docs.hp.com/en/1219/tuningwp.html

Also, you can use kcweb to tune these parameters via a browser.

-Arun

[Muthukumar_5]

Use kctune utility or sam to get informations and tune variable.

-Muthu

[Muthukumar_5]

Example article:

http://www.informit.com/articles/article.asp?p=392277&seqNum=2&rl=1

with ktune.

with sam:

sam -> kernel configuration -> configurable parameters

will give that.

-Muthu

[RAC_1]

nbuf and bufpages kernel parameters are there. Others are not. maxusers and maxswapchunks were used in formulaes to calculate some other parameters. e.g. maxusers was used to calculate nproc etc in older OS versions.

You can set nbuf and bufpages as you want. You can also set dbc_max_pct and dbc_min_pct to single value to do what you could do with bufpages and nbuf.

[Thierry Doppler]

Hi,

Thanks you for your anwers, but all these parameters don't appear in kcweb or sam with HP-UX 11.13 on Itanuim ! This is my problem !

Thierry

[Arunvijai_4]

Have you tried with kmtune or kctune ?

# man kmtune or kctune will give you more information.

-Arun

[RAC_1]

kctune and kcweb may not report them, but they are there. (except maxusers and maxswapchunks)

use - kctune or kmtune )kmtune is still there as way to access kctune

OR
betterm, directly query the kernel itself.
echo "nbuf/d" | adb -k /stand/vmunix /dev/kmem

[Muthukumar_5]

11.23 is supporting kctune to tune kernel parameters. See kctune man page. Or else use sam or adb to udpate variable.

-Muthu

[Thierry Doppler]

Yes I tried kcweb, kmtune, kctune and SAM.

No trace from these parameters on my HPUX IA 11.23 !

They are hided or doesn't exist any more on this HP-UX Version ?

[RAC_1]

what about following??

echo "nbuf/d" | adb -k /stand/vmunix /dev/kmem

[Arunvijai_4]

Take a look at this link,

http://docs.hp.com/en/5990-8153/ch05s20.html

[HP-UX Kernel Configuration for 11.23]

-Arun

[Thierry Doppler]

Hi RAC,

Here the result :

#>echo "nbuf/d" | adb -k /stand/vmunix /dev/kmem
adb: info: Option -k is deprecated.
nbuf:
117831

Can we change this value ?

[Muthukumar_5]

kctune nbuf

what it is saying? Try to change as,

# kctune nbuf=0

what are you getting?

-Muthu

[Thierry Doppler]

#kctune nbuf
Tunable Value Expression
nbuf 0 Default

#kctune bufpages
Tunable Value Expression
bufpages 0 Default

#kctune maxswapchunks
ERROR: There are no tunables matching the name you specified.

And what's about this :

#echo "nbuf/d" | adb -k /stand/vmunix /dev/kmem
adb: info: Option -k is deprecated.
nbuf:
117831

[Richard Perez]

comments:
-maxusers doesn't exist in 11.23 (see http://h21007.www2.hp.com/dspp/tech/tech_TechGroupTipDetailPage_IDX/1,2367,10402,00.html#5329)
-you should use kctune to set kernel parameters
-As nbuf/bufpages are being deprecated, they don't show by default on kctune. Use "kctune bufpages" to get current value of bufpages, same for nbuf

Regards

[Don Morris_1]

maxswapchunks was obsoleted in 11.22. Long gone in 11.23. (For the curious, the kernel auto-tunes itself for the functionality of maxswapchunks). swchunk is the only tunable you need to care about when sizing your swap. Set that to at least (BYTES OF INTENDED SWAP) / (16Mb).

For maxusers, the man page *does* detail which tunables you may want to set (those that used to have dependencies on maxusers). nclist, nfile and nionode are all listed (Second paragraph of DESCRIPTION).

For nbuf and bufpages (as the man pages indicate) - these are now private [don't show up in the default listing, but you're allowed to set them if you wish] to get people to migrate to the new tunables dbc_min_pct / dbc_max_pct.

Simply put, SAP needs to update their guidance. If you have SAP support - contact them and get them to give you updated guidance. If not (or you don't want to wait for it), look at what they're asking you to do... i.e. if bufpages is 3% of your memory in their recommendations, set dbc_min_pct and dbc_max_pct to 3, etc.