Kernel for Oracle.

[N.S. WARGHADE]

Hello to all members,

We have hp-ux 11.x on L-class server with
1 gb ram and database is on RAID-5 file system
(oracle 7.3.4.5)

How effectively we can tune the hp-ux kernel for optimium performance of database.

thanks in adv.

[eran maor · Accepted solution]

Hi


it is very dep. on the config of the site .
more info you can found at this answer :
http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x7acacf38d6bdd5118ff10090279cd0f9,00.html

but one thing i will check it the bufer cashe of the computer .
if your system is not an nfs server ( dont think that oracle server is will be an nfs server ) i will check the :
dbc_max_pct
dbc_max_pct defines the maximum percentage of memory to be used by dynamic buffer cache.

i will define it at 10 % to free memory for the oracle , the default is 50 %

you also need to check
dbc_min_pct
dbc_min_pct defines the minimum percentage of memory to be used by dynamic buffer cache.

i will define at 5 % .

this will improve the aloc of the memory .

be also be advise of all the kernel params that you can read :
http://docs.hp.com//hpux/onlinedocs/os/KCparams.OverviewAll.html

[Roger Baptiste]

hi,

The first thing to look for would be the
buffer cache parameters :
dbc_max_pct
dbc_min_pct
this should be set to 10% and 5%.

The other important kernel parms are:
data/stack size
maxdsiz
maxssiz
semaphores:
semmns 512
semmni 512
semmap 550
semume 50
semmnu 100
sharedmemory
msgmax 32768
msgmnb 32768
msgmni 150
msgseg 7168
msgtql 256
user/processes
maxusers 100
(this will increase nfile, nproc)

HTH
raj

[Andreas D. Skjervold]

Hi

Oracle performance tuning is a large area to cover, but in short what is said is that a out of the box Oracle installation generally is very well tuned.
The importing things to consider is:

- datafile placement: These MUST be placed on several different diskdrives.

- Buffer cache; the more of the commonly used data you can get fitted into the buffer cache, the faster data can be retrived during selects.

But the most important thing in all perfomance issues is statement tuning; How can you get your application efficient. SQL statements / indexes / optimizer behavior.... This is the BIG issue...

But ofcours a good tuned HP-UX kernel is always preferable.

But 7.3.4 ? Several things have improved since then. You might consider upgrading.

Andreas

[Sanjay_6]

Hi,

You can start by using the tuned kernel parameter set for oracle Server provided by hp. to do so, use sam --> kernel parameters --> configuratble parameers --> Apply tuned parameter set --> Select General OLTP / Datbase server system.

Set this parameter set, rebuild the kernel and reboot. Hopefully you won't be required to retune your parameters for oracle performance.

Hope this helps.

Regds

[A. Clay Stephenson]

If you choose to follow Sanjay's advice on apllying a tuned parameter set make sure that you check the timeslice value afterwards. Most of those stupidly set it to 1 (it should be 10). You will have a real dog if you leave it at 1.

Clay