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HP-UX Kernel Parameters tuning for Oracle 8.1.7

Dharshana Jayasuriya
Occasional Contributor

HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi All,

We have a Oracle 8.1.7 database in HP-UX 11.0. At the moment, the databse performance seems to be very low.(We are accessing the database through JDBC) While we are looking at the Oracle side, is there something we can do to improve Oracle performance by tuning Kernel Paramaters ?

The server has 2 GB RAM and enough swap space.

Specially any suggestions on parameters such as dbc_max and min pct, nproc, maxuprc etc.. is greatly appreciated.

Thanks!

Dharshana
9 REPLIES
Michael Tully
Honored Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Keely Jackson
Trusted Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi

We run oracle 8.1.7 on k580, hpux 11.0, 2Gb ram. We applied the database monolithic kermel tuned set and the parameters you mentioned are set to:

db_max_pct 20
db_min_pct 5
nproc 1461
maxupc 1168

Whether these are optimum I don't know but we have no problems with db performance.

Cheers
Keely
Live long and prosper
Dharshana Jayasuriya
Occasional Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi Guys, Thanks for the responses so far.

Let me add some more details:

The server is L2000 with 2 CPUs. Swap 4 GB.


# swapinfo ???ta

Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4194304 0 4194304 0% 0 - 1 /dev/vg00/lvol2
reserve - 582468 -582468
memory 1627124 519276 1107848 32%
total 5821428 1101744 4719684 19% - 0 -
#

I am attaching the present values of all the Kernel Parameters (Please note that these values are transistion values until we find the best mix).

Keely Jackson
Trusted Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi Dharshana

I am by no way an expert on these things, but I ssuspect that your db_max_pct is a bit on the high side.

When you say 'performance seems to be very low' what exactly do you mean?

Cheers
Keely
Live long and prosper
Dharshana Jayasuriya
Occasional Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi Keely,

I agree with you. I think it has been set to 50% now. (not by me!!). So, I would like to reduce it at the same time with other changes.

The application we are using has been bench marked with another Oracle database (with a differnt model of HP machine with differnt config-so it is difficult to compare)and found it provides 5 times faster responses than what it is doing with this database. Obviously, there could be Oracle parameters themselves and network issues as well. We are also looking at these issues also separately.

cheers,

Dharshana
Stephanie Nicholls
Frequent Advisor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi Dharshana

We run 3 production db's on a L Class (4CPU's and 5Gb RAM)

Ive attached my kmtune for you to have a look at, by the way I dont think mine is ideal but the db's run ok.

Just looking briefly I would say your timeslice is too low and your dbc_min_pct and dbc_max_pct are too high.

Additionally - here is a list of standard kernel changes we had at one of my previous sites - these would go onto any HP oracle server.

dbc_max_pct 10
max_thread_proc 256
maxdsiz 0X40000000 (32 bit Maximum : 0X7B03A000 ??? 2Gb)
maxdsiz_64bit 4294967296
maxfiles 1024
maxfiles_lim 2048
maxuprc 400
maxusers 512
msgmnb 65535
msgseg 32767
msgssz 32
msgtql 2046
ncallout 8192
nflocks 800
nkthread 2048
semmni 512
semmns 1024
semmnu 256
semume 100
shmmax 0X40000000
shmmni 256
shmseg 200

Hope this is of some help.

Cheers

Steph
Yogeeraj_1
Honored Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

hi,

Again,
dbc_min_pct 5
dbc_max_pct 10
should be OK.

also, i would leave nproc = (20+8*MAXUSERS)

Hope this helps!

Regards
Yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Hamdy Al-Sebaey
Regular Advisor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

Hi Dharshana,
Just have a look at this sight may be it 'll help you in the future to know more about the kernel.
http://docs.hp.com/hpux/onlinedocs/939/KCParms/KCparams.OverviewAll.html or
http://docs.hp.com/hpux/os/11.0/index.html, then choose for system administration.

Regards,
Hamdy
Thanks for sharing knowledge
A. Clay Stephenson
Acclaimed Contributor

Re: HP-UX Kernel Parameters tuning for Oracle 8.1.7

This is a very badly tuned beast!!!

1) Your timeslice is set to 1. BAD!!! BAD!!! BAD!! Set it to 10 and leave it there. Your box will context switch like a madman.

2) You have bufpages set to nproc * 3 (2068 * 3) = 6204 pages or 24MB. This is much too small. Either set bufpages to something around 300MB (76800) or use dynamic buffer cache but set dbc_max_pct to no more than 20%; 10% might be better. In that case you would set bufpages to 0 and leave nbuf at 0.

I think you will immediately see great improvement if you do this.

Regards, Clay


If it ain't broke, I can fix that.