Re: Maximum Instances in a Unix Server

Jordi Ruana wrote:

> Hello everybody,
>
> I'm a unexperienced and just started DBA
>
> I'm changing our Unix infrastructure servers (Alphaserver 1000 and
> RS6000) in order to be able to run five Oracle instances in only a unix
> Server box. The instances aren't too big (maximum 30 GB the big one).
> The number of users is about 2-3 at max doing queries with Oracle
> Discover. There isn't OLTP.

I run similar types of systems, although some much bigger.

I say be very careful about putting 5 instances of this type on one server. Even with just a few users, large DSS style queries can drive a server through the floor. And you are looking at 5 instances...

Without knowing *a lot* about the dynamics of your system it's impossible to make solid recommendations. I'd first question *why* you want to put this on one box? It might actually work out cheaper to use smaller, multiple servers. And that way you don't loose the lot if one server goes done. And if you are concerned about storage management, that can always be concentrated outside of the servers for easier management. All I'm trying to say is think before you leap, and keep an open mind.

If you do go the one server route, then *partition* at all levels: memory, disk drives/adapters and CPU. Try to separate the instances as much as possible in terms of the hardware they use, that's the only way you'll be able to monitor/tune them realistically. Maybe even look at a Numa sytle server. And make sure you leave yourself with plenty of 'head room' for future growth.

Like I said, I'd still go for at least a couple of servers, but the choice is yours. Monitor whatever you do and be prepared to admit mistakes and buy an extra server if you have to. Get in some loan kit to 'try before you but' just to be on the safe side.

And why ditch the RS6000 from your range of choices? IBM S70 is one hell of a scalable server, and so are some of the Sun boxes.

Later,

Steve Phelan

(Oracle 7 & 8 OCP)

>
>
> The Question is: could be that I'm doing crazy things or perhaps
> somebody has any experience on this one?. Also I'm trying to size the
> right machine (Digital or HP)
>
> Thanks in advance
>
> Jordi Ruana
Received on Thu Feb 25 1999 - 16:32:40 CST