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Re: Oracle 9i performance

 
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Shivkumar
Super Advisor

Oracle 9i performance

Hi,

We are running Oracle 9.2.xx RAC with ADR (Advanced Data Replication). We are seeing some disk i/o performance issue.

The Oracle is installed HP's xp series 1024 SAN disk volume.

Can someone suggest how to find out the bottleneck ?

Thanks,
Shiv
16 REPLIES 16
Bill Hassell
Honored Contributor
Solution

Re: Oracle 9i performance

This is a very simple description of 90%% of performance problems, namely, lots of disk activity and users (and/or DBAs) complaining about performance. Yes, the disk is very likely the bottelneck so you need to reduce the number of disk requests. One way is to reduce the number of users or processes that are accessing the database (probably an unacceptable solution). Another way is to replace all the disks with RAM or solid state disks. But unless you have unlimited amounts of money (a solid state disk replacement for a large XP 1024 would be millions of dollars), that is probably not a solution.

So the first question is how much RAM do you have and what is the size of the HP-UX buffer cache? The (very poor) default for the buffer cache is 50% of RAM. This should be set to a fixed value (in case you add more RAM) by setting bufpages to about 204800 to 409600 (800 to 1600 megs in 4k pages).

The rest of the performance questions must be characterized by your DBAs in terms of SGA usage and index (or partial index or no index) usage. If the database is not monitored, indexes may become severely unbalanced and may be silently bypassed depending on the version of Oracle. If SGA is just a few hundred megs, you'll need the DBAs to look at the performance gains (meaning less disk I/Os) possible with multi-Gb SGAs. Of course, you'll need many Gb of RAM.

Optimizing Oracle will gain the biggest performance improvement. After optimizing RAM, you may find the the number of CPUs is limiting performance, but you'll need to take measurements and correlate them with Oracle stats.


Bill Hassell, sysadmin
Steven E. Protter
Exalted Contributor

Re: Oracle 9i performance

Shalom Shiv,

Free tool:

http://www.hpux.ws/system.perf.sh

Glance Plus will also help.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Shahul
Esteemed Contributor

Re: Oracle 9i performance

Hi,

It's a bit tricky to handle. There can be various reasons why an environment is slow. Check for the following,

1. Check your hard disk I/O by glance and perfview. If any of the hard disk is loaded due to high I/O, it slow down the system performance. It may be because poor storage management like improper RAID or mirror config, improper stripe size etc.

2. Check with DBA's if the oracle performance parameteres are tuned to your environment.

3. Check the memeory, files, swap, processes related Unix kernel parameters are tuned correctly.

4. It can also because of lack of memeory, in this case, you may need to increase the physical memory.

Hope this helps,

Best of luck
Shahul
Shivkumar
Super Advisor

Re: Oracle 9i performance

What are parameters to be tuned with regard to Oralce 9.2.x.x RAC ADR on HPUX 11i ?

If someone can list then i can ask my DBA to verify them ?

Regards,
Shiv

Shivkumar
Super Advisor

Re: Oracle 9i performance

Also, Is it okay to suggest to install another network cards on machines running oracle and increase the bandwith of network i/o by combining the speed of 2 or more network cards by trunking technology ?

Regards,
Shiv
Hein van den Heuvel
Honored Contributor

Re: Oracle 9i performance


>> What are parameters to be tuned with regard to Oralce 9.2.x.x RAC ADR on HPUX 11i ?

Don't worry about HPUX untill you have the appropriate understanding of the Oracle performance done.

Your DBA shoudl be able to tell you the critical wait events. The DBA shoudl be able to tell you (with the help of Oracle STATSPACK data ) whether the application has more or less enough SGA, or could use more.

>> Also, Is it okay to suggest to install another network cards on machines running oracle and increase the bandwith of network i/o by combining the speed of 2 or more network cards by trunking technology ?

No, that makes no sense at all untill you have an indication that network performance is at all relevant for the problem on hand.
You indicate/suspect you have a disk access proble. If you had a serious network problem, then you would not have a disk problem (that's the thing with bottlenecks.. you generally have only on at a time. Fix the current one, and you may or might not run into the next bottleneck (Most likely you will :-).

Mind you, with Oracle RAC active, the network may be heavily loaded for locking and cache consistency, but there again your DBA can tell you whether this is the case through statspack. Moreover, if this is the case your first step should probably be to give oracle RAC a dedicated connection for its protocols, rather then increasing generic bandwith through aggregating.

Good luck!
Hein.
Leon Allen
Regular Advisor

Re: Oracle 9i performance

Use glance plus to identify the load distributuion.
Then distribute the load - I have even gone to the extent of putting some file on local SCSI disks. My rational for this was the local disks are on a completely seperate controller (local SCSI cf. SAN HBA). Any 'work' going to the local scsi is a load of the HBA and SAN disks.

The files you put on local SCSI depends on available space, but can be all or some of redo logs, undo tablespace, temp table space..... up to you.

Another thing which may help is turn off logging on your index tablespaces (ie no redo log entries generated)

Cheers!

Leon

Time's fun when your having flys (ancient frog saying)
sysadm_1
Valued Contributor

Re: Oracle 9i performance

HEllo Shiv,

Attaching HP/Oracle documents which explains the kernel parameters and other settings for oracle 9i RAC.

Cheers!!
sysadm
sysadm_1
Valued Contributor

Re: Oracle 9i performance


check this toooo

sysadm