Re: Oracle: how many instances?

Thank you so much for your reply. I realize that 25 instances with the configuration below is a little ambitious. Truth be known, I will more than likely stop at around 15 to 20 instances and marketing is telling me that many of the instances will have 5 or less users.

You are right about the memory. I had actually already told them that I would need 4GB of RAM to support that many instances which still is not ideal but I am planning on creating small SGA's for some of the smaller instances with 2 to 3 users.

The system will have 17 to 18 disk drives (5 arrays of RAID-1 so I will actually have about 11 to 12 drives to work with). This will allow me to totally separate tablespaces, logs, etc. and therefore eliminate any I/O contention within an instance. However, I will have I/O contention between the instances. I am running the same drive configuration on our development machine and have not noticed any performance problems however, the number of users on this development machine is significantly less than I am planning for this new machine.

I have spoken to the network guys and they don't seem to be real concerned about the network traffic. And regarding the DBA task, it is my understanding that I will be getting an assistant soon (I hope!). However, you raised a good point about the processes. I will be doing some more research into that.

Based on everything I have said above, do you think that I am still reaching or is 10 to 15 instances all that I can really hope to run on this server? Thank you again for your reply and any more information that you or anyone else can supply will be greatly appreciated.

Thanks

In article <931t8h$klc$1_at_soap.pipex.net>,   "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote:
> I should of course have added CPU
>
> 25 instances times say 15 processes for a lightly loaded instance is
 going
> to eat pretty heavily into the capacity of two cpu's
>
> --
> Niall Litchfield
> Oracle DBA
> Audit Commission UK
> "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in
 message
> news:931hl9$enc$1_at_soap.pipex.net...
> > I'm not that familiar with Linux, my experience is mostly NT with
 some SCO
> > (and I'm fed up with the flame wars that comparing to ms always
 seem to
> > provoke) however it would seem to me that you are being somewhat
 ambitious.
> >
> > There are two key areas thatI would suggest you consider (well
 actually 3
> > but I can't speak with great authority on the third)
> >
> > Memory.
> >
> > Your box has 2gig of RAM. allocating 2/3rds of that to 25 instances
 gives
> > according to my calculations just over 50MB of RAM per instance.
 This is
> > unlikely to produce great performance
> >
> > Disk.
> >
> > You don't say how many or what spec disks you will be using, but
 you are
> > quite likely with 25 instances to get contention between the
 instances for
> > the same disk resources.
> >
> >
> > The third area is network connectivity, how good are your boxes
 network
> > interfaces and how well will they cope with say 350 simultaneous
> > connections?
> >
> > In addition to all this standard DBA tasks, such as backup and
 archive log
> > management etc will become somewhat more complex with 20+ instances.
> >
> > regards
> >
> >
> > --
> > Niall Litchfield
> > Oracle DBA
> > Audit Commission UK
> >
> >
> > <bsidba_at_my-deja.com> wrote in message news:9309ei$ti6
 $1_at_nnrp1.deja.com...
> > > Why yes, it is a serious question. What is wrong with connecting
 200
> > > to 500 users to a Linux box? I am relatively new to Linux but I
> > > figured that I could get better performance and stability from
 Linux
> > > than NT. Your input is appreciated. Thank you
> > >
> > > In article <93061t$8ajtf$5_at_ID-62141.news.dfncis.de>,
> > > "Sybrand Bakker" <postbus_at_sybrandb.demon.nl> wrote:
> > > > 10 to 20 users would mean between 200 and 500 users connecting
 to a
 Linux
> > > > box.
> > > > Is this supposed to be a serious question?
> > > >
> > > > Regards,
> > > >
> > > > Sybrand Bakker, Oracle DBA
> > > >
> > > > <bsidba_at_my-deja.com> wrote in message news:92vbj4
 $1bn$1_at_nnrp1.deja.com...
> > > > > How many Oracle instances can I run on one server and still
 have
 good
> > > > > performance and reliability? Each instance will only have
 about
 200MB
> > > > > to 300MB of data and about 10 to 20 users. The server will
 be a
 dual
> > > > > 933MHz Pentium III Zeon with 2GB of memory running Oracle
 8.1.7 SE
 on
> > > > > Red Hat Linux 6.2. I was hoping I could run 20 to 25
 instances. Is
> > > > > this out of the question? I have looked through the forums
 and have
> > > > > been unable to find a similar question and I was hoping that
 someone
> > > > > had experience with this many instances on one server. Your
 input
 will
> > > > > be greatly appreciated.
> > > > >
> > > > > Thank you
> > > > >
> > > > >
> > > > > Sent via Deja.com
> > > > > http://www.deja.com/
> > > >
> > > >
> > >
> > >
> > > Sent via Deja.com
> > > http://www.deja.com/
> >
> >
>
>

Sent via Deja.com
http://www.deja.com/ Received on Thu Jan 04 2001 - 08:40:06 CST