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Oracle 9i recommended kernel parameters?

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Martin Mc Gahon
Occasional Visitor

Oracle 9i recommended kernel parameters?

Hello all,

I am doing an oracle DB install on a hpux system.

With the following details:

HPUX server details:
model: rp3440
processors: 4
hpux: hpux 11i (11.11) 64 bit
physical mem: 16 G
Swap: 4 G

Oracle Details:

Oracle: for 64 bit
SGA_max_sze parameter is to be set between 12 and 15G
Number of oracle datafiles will be 5000
Number of users will be approx 30

I have already changed the following HPUX Kernel Params to the following values:

dnlc_hash_locks 512
max_thread_proc 256
maxdsiz 1073741824
maxdsiz_64bit 2147483648
maxssiz 134217728
maxssiz_64bit 1073741824
maxswapchunks 16384
maxtsiz 0x4000000
maxtsiz_64bit 0x40000000
maxusers 512
msgmni 4096
msgseg 32767
msgtql 4096
nstrpty 60
semmni 4096
semmns 4096
semmnu 4092
shmmax 8589934592
shmmni 512
vps_ceiling 64

And also have seen it recommended to change the following hpux kernel parameters on some related websites:

parameter: Current Recommended

nbuf 0 50000
bufpages 0 nbuf*2
default_disk_ir 0 1
maxfiles 60 4096
maxfile_lim 1024 8192
nfile 7790 8192
nflocks 4096 8192
nproc 4096 8192
ncsize 9896 25120
maxuprc 3687 nproc - 4

Fisrtly are the values of the parameters that I have already changed Ok? And secondly is it ok to change the values to the recommended parameters. I just need to know if these changes will not affect the operating systems performance to much. The main thing is also to make sure that oracle can have 5000 datafiles open at one time and that the SGA size can be set between 12 and 15G.

Any help much appreciated.

Thank You

Honored Contributor

Re: Oracle 9i recommended kernel parameters?

Martin, If you've really got 5000 database files - then you need to set the maxfiles parameter to at least that high (so that Oracle can start the database).
Also, your nfile needs to be the total number of files handles that the system will have open at once. So, besides holding open the original 5000 by Oracle itself - each individual PGA space (user shadow process on each users' behalf) will have many files open itself. So, if you're going to have 100 users, each with 50 or so files open per shadow process - that's another 5000 right there. This needs to be bigger.
We are the people our parents warned us about --Jimmy Buffett
Indira Aramandla
Honored Contributor

Re: Oracle 9i recommended kernel parameters?

Hi martin,

The parameter MAXDATAFILES value is stored in the CONTROL FILE upon database creation. This is the "hard" limit on the number of datafiles which can be associated with this particular database.

The parameter "DB_FILES" is specified in init.ora. This is the limit on the total number of files associated with a particular INSTANCE of a database. This parameter can be changed simply by editing the init.ora and restarting the database, it is considered a "soft" limit.

In 9i and above, it is even softer. The OS level only comes into play when you try to set db_files or maxdatafiles higher than the OS can handle.

The default and the range of values of maxdatafiles and db_files are operating system specific.
There is a limit on MAXDATAFILES. Each platform uses a port-specific number of bits to store the ORACLE file numbers. Thus, MAXDATAFILES is limited by this number. This limit is imposed by the limit on control file size (20,000 blocks) with a 4K block size. In 9i, larger block sizes are supported, thus with DB_BLOCK_SIZE=8192 there can be up to 65,534 datafiles (same limit as other platforms).

Now about SGA, there is a Variable Size component of the SGA. One of the components that comprises the Variable Sixe is the Overhead. Various parameters influence the SGA size that constitutes the overhead. Some of the init.ora parameters that inflence the overhead part of variable component are: db_files, open_cursors and processes.

Attached is a document that describes the above.

Your HPUX Kernel Parameters looks close enough to what Oracle 9.2 recommends on HP-UX 11.11. DB_FILES (MAXDATAFILES) depends on nfile and maxfiles of the kernel parameters.

And finally when you are installing Oracle 9i on a hpux system there is a BUG.
Per HP Bug (Doc ID: KBRC00003627)
NOTE: This bug is not applicable to 11.22,11.23

The default 64bit OS installation does not create a few required X library symbolic links. The following symbolic links need to be created:
cd /usr/lib
ln -s /usr/lib/libX11.3
ln -s /usr/lib/libXIE.2
ln -s /usr/lib/libXext.3
ln -s /usr/lib/libXhp11.3
ln -s /usr/lib/libXi.3
ln -s /usr/lib/libXm.4
ln -s /usr/lib/libXp.2
ln -s /usr/lib/libXt.3
ln -s /usr/lib/libXtst.2

Never give up, Keep Trying

Re: Oracle 9i recommended kernel parameters?

Hi Martin.

Oracle & HP кecommend for kernel this Ñ arameters


Re: Oracle 9i recommended kernel parameters?

But I use here these and productivity is better
Cem Tugrul
Esteemed Contributor

Re: Oracle 9i recommended kernel parameters?

Hi Martin,

Please also have look my attachment...
Also take the kernel param;


These are really important kernel param
while using Oracle9i.
Also consider SGA size can be increase
on high physical mem systems like yours(16Gb)

Good Luck,
Our greatest duty in this life is to help others. And please, if you can't
Cem Tugrul
Esteemed Contributor

Re: Oracle 9i recommended kernel parameters?

attachment is here..
Our greatest duty in this life is to help others. And please, if you can't
Fred Ruffet
Honored Contributor

Re: Oracle 9i recommended kernel parameters?

There are 2 links things you may read :
. Oracle prerequisites when installing on Unix server
. HP cookbook for Oracle



"Reality is just a point of view." (P. K. D.)
Martin Mc Gahon
Occasional Visitor

Re: Oracle 9i recommended kernel parameters?

Hi All,

Thank you very much for the answers above. I have reviewed them and changed my OS parameters. I will not know the benefit until the system is in production. But I will ley you know how it goes and give my final settings at that stage.