Tuning the Kernel

[Pearse Mc kiernan]

I was wondering if there are any parmeters that would need to be tuned if I had
about 500 users connecting to
a Oracle database. When I use the "top" command I can see up to 220 processes
running and it takes a noticeable when the system goes to run a command when
there is alot of activity in oracle.Any suggestions?

[Dan Hull]

Oracle has recommended kernel settings available on their web site. The only
one I know I would set is dbc_max_pct, which I would reduce from the default
50%. If you have under 512M of RAM, try setting it to 30%. If you have 512M-1G,
try 20%, and if you have over a Gig of RAM, try 10%. This should save you a
considerable amount of RAM which can then go to other things.

[Anthony Goonetilleke_1]

I am not an Oracle guru but I seemed to remeber Oracle having two modes shared
mode and dedicated mode. I think if you have many users i.e 500 you will get
better performance in shared mode. I remeber reading some docs on this at the
Oracle web site.

[Navied Yousuf]

Greetings,
Oracle installation guides generally points to setting shared memory and semaphore parameters. Not familiar with the tuning recommendation on their web site. However, system tuning is very much related to application and the system configuration.
At least check you shared memory and semaphore settings to ensure that they optimized for your app. ipcs -am and ipcs -as will tell you if your SGA is spliting (or not) into two shared memory segments. If applicable also check if SGA is pinned in shared memory. There are several other parameters that are to be checked. Some specific to 11.0. Provide more info on system configuration and current tuning. You can use system file, sysdef and kmtune commands to get this information.
Cheers.