Re: Recommended stripe depth for Oracle on a Raid?

Daniel Morgan <damorgan_at_x.washington.edu> wrote:

>I would dispute that based on benchmarking we performed just this year
>with the latest
>hardware and configurations.

I would expect Raid 10 being faster, no question. The question is: How much faster? In my very short DBA life I have learned that 30% of speed increase is almost nothing. At least it is not worth the sacrifice for space compared to Raid 5. As you surely know, the true source of performance is the application itself. There seems to be no limit in potential performance improvement there. This is because most people who design the schema and write SQL/front_end don't bother about performance issues.. until it is too late.

It happened a couple of weeks ago, that some developers asked me for help, because the instance of a Webbased DB product running on a notebook (a kind of demo platform) did not respond fast enough and the browser timed out. I intervened and tuned almost everything a DBA can do in one strike (since it was not a production environment). They were very impressed since afterwards the DB was working really faster. But this is a seldom case. I was having a hard time trying to tell them to be aware how Oracle executes their SQL statements. They don't seem to be aware that SQL is not a procedural programming language and that one has to put an eye on the execution plan. They rather expect ME to somehow make things faster. Jesus!

In my opinion, DBAs who care whether hot data are contained in the outer zone of the disk (where linear speed is larger than towards the center of the disk) must be crazy. I have seen improvements from two days to several seconds... on the application side. No Raid configuration will ever achieve that. It is not worth even trying.

Rick Denoire Received on Sun Nov 02 2003 - 17:32:24 CST