Re: SAME methodology opinions?

"Tanel Poder" <tanel@@peldik.com> wrote in message news:<3e6dec1d_1_at_news.estpak.ee>...
> Hello!
>
> Simple, I keep hearing this too much, that adding more cache, memory, CPU is
> all you need and forget about planning your IS/DB/HW.
> And I just talked to a Hitachi salesman few weeks ago, that told me the same
> story.. especially with the one that EMC can't handle IO at all, etc..
>
> I'm not against the SAME methodology at all - it can help to lower the
> administration costs of small to medium databases with small performance
> impact. Of course, if one doesn't/can't plan a physical database structure
> properly, SAME would be a safe bet. But if you do have a little common sense
> and understanding of RDBMS'es, you can achieve better results with separate
> disks. The question is, which is more expensive, DBA knowledge for planning
> or hardware (software/licenses).

The Hitachi I worked on had a faster data transfer rate and lower published error rate than the built-in [HP and Sun] disks/controllers.  No common sense there I guess! :-)

The best part was watching the DBA from Oracle struggle over the concept of where to put the most speed-sensitive data files.

>
> But what I'm strongly against, is the idea that cache is the cure for all
> worlds problems, e.g. if your DB gets slow, just get more cache (or even buy
> CPUs). As long as you don't cache every single bit of your data, the disks
> will always be a bottleneck.

Well, not if the cpus or cache are the bottleneck! And I'm continually amazed that that is the case (except when I realize what Oracle is doing with buffer scanning and latches and etc.). In point of fact, I'm working on two systems right now with the same I/O, same software, but different CPU's and memory (and K-class vs. N-class HP).  Guess what I see? The N-class has enough horsepower to show the disk as a bottleneck. And cache might well help that. But the person who decides will probably spend what little money is left on more memory, and I can't honestly disagree.

>
> Tanel.
>
>
> > > Seems that you are a novice salesman at Hitachi?
> > >
> > >
> > > Definitely a Hitachi salesman.

I'd like to be their DBA :-)

> > >
> > >
> > > The situation is getting more and more extreme. Every day.

Agreed.

> > >
> >
> >
> > Care to elaborate and share your insight ?

jg

--
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"Almost all databases have one thing in common: change." - Advanced
Oracle Tuning.