In my belief the valid reasons for having an application server/layer are:
- fail-over/system availability: the application layer can be divided
over many different nodes; failure of one will not result in system failure.
- scalability: the application layer is deployed on a number of
different, relatively cheap nodes - this number can easily be increased.
- load balancing: this prevents one node to be a bottleneck while others
have nothing to do.
(But maybe there are more reasons...)
So, the fact that the application layer is deployed on many, cheap nodes
(servers) allows it to offer the services that made it imperative within
the 3-tier concept.

BUT:
Since the introduction of Oracle10g, the typical enterprise scale
database hardware will shift from one very expensive, high-end server to
a farm of standardized, commodity priced components/servers. This means
that you no longer need an application layer to have a scalable, fault
tolerant system with flexible load balancing: the database layer can do
this for you now! (Besides, the fault tolerance of the application layer
wasn't of much use if you're database goes down.)

So my conclusion is that for many – if not most – Oracle Internet
applications, the application layer will become less important with the
introduction of Oracle10g. The data layer will take over! Apart from
some simple tasks like connection pooling and processing XML into a
presentation format or a web service – and even these tasks can be done
by the Oracle database! - there no longer seems to be a valid reason
for having a robust application server.

I'm very interested in other people's views on this subject.

Regards,

Roel

Hello Roel,

IMHO:

For a big systems you still need to architect separate layers: you may
need 100-200 database servers, but multiple thousand's of application
servers at least, separated by functionality, geo-location, etc.

As for the DR failover architecture it is much more transparent to
fail-over database layer with almost no interruption to application vs.
dragging to DR whole system.

Regards,

Ron
DBA Infopower
http://www.dbainfopower.com
Standard disclaimer:
http://www.dbainfopower.com/dbaip_ad...isclaimer.html




"rcf<_no.SPAM_> @wxs.nl>" <"rcf<_no.SPAM_> wrote

"Ron" <support (AT) dbainfopower (DOT) com> wrote

If you have 100-200 database servers serving the same app, you have one hell
of a bad app.


--
Niall Litchfield
Oracle DBA
Audit Commission UK

Hello Niall,

All depends on scale and scope of application. When It is coming to
real-world implementation things don't scale like in theory.

For example you may need 10 database servers just to support user
sign-ins and registrations.

Regards,

Ron
DBA Infopower
http://www.dbainfopower.com
Standard disclaimer:
http://www.dbainfopower.com/dbaip_ad...isclaimer.html




"Niall Litchfield" <n-litchfield (AT) audit-commission (DOT) gov.uk> wrote

Ron wrote:

At Boeing a few years back, when the company had more than
200,000 employees, it was all handled with a single server.
And we often had 10,000 simultaneous connections: Ask me
how I know. ;-)

How many simultaneous users do you need to require 10 database
servers to support user sign-ins and registrations? And where
has this been implemented?

Thanks.

--
Daniel Morgan
http://www.outreach.washington.edu/e...ad/oad_crs.asp
http://www.outreach.washington.edu/e...oa/aoa_crs.asp
damorgan@x.washington.edu
(replace 'x' with a 'u' to reply)

On Fri, 13 Feb 2004 08:01:45 -0800, "Ron" <support (AT) dbainfopower (DOT) com>
wrote:


Could you either please stop posting this bullshit, or include your
disclaimer under every line you post here?


--
Sybrand Bakker, Senior Oracle DBA

Hello Sybrand,

I am really sorry to say that, but You probably have no clue about
real-world systems and how to scale them.

Friend of mine currently supports site, that needs not 10, but 16 of user
signing / lookup servers.

Just think about sites like AMAZON, Yahoo and EBAY and stop posting flames
and harassment.

Regards,

Ron
DBA Infopower
http://www.dbainfopower.com
Standard disclaimer:
http://www.dbainfopower.com/dbaip_ad...isclaimer.html



"Sybrand Bakker" <gooiditweg (AT) nospam (DOT) demon.nl> wrote

Ron wrote:

Ron ... please stop this nonsense. I am in Seattle and many of my
students are at Amazon or are former Amazon employees. You are just
making this stuff up and it is neither appropriate not professional
to do so.

Sybrand probably knew more about Oracle five years ago than you will
know five years from now.

If your point is to make friends and influence people to do business
with your company you are proceeding like a US President at a meeting
of the European Union.

--
Daniel Morgan
http://www.outreach.washington.edu/e...ad/oad_crs.asp
http://www.outreach.washington.edu/e...oa/aoa_crs.asp
damorgan@x.washington.edu
(replace 'x' with a 'u' to reply)

Hello Daniel,

Not having real life experience does not gives a right to flame.

Why don't you accept that things exist that bigger that Sybrand(or you in
a fact) can imagine.

I myself (not at dbainfopower) currently work at site that serves 50
Billion (50E9) logical reads a day.

I do not discuss Sybrant's (or mine) Oracle DBA skills. He may be a fine
DBA fellow, but he is very limited to his own experience.

Ron


"Daniel Morgan" <damorgan@x.washington.edu> wrote

On Fri, 13 Feb 2004 15:26:04 -0800, "Ron" <support (AT) dbainfopower (DOT) com>
wrote:

Please stop the insults. If I would have been an US citizen, I would
sue for your assertion I have no real world experience. I would win
the case in 5 seconds, and you would look ridiculous, even more
ridiculous than your are already looking now. It is always the same
with you: as soon as you stand corrected you resort to insult your
opponents, just like the Niemics, Burlesons, and Aults of this world
always do. Probably the main thing you learned as a DBA is how to
cover your ass. And even in that you fail miserably by resorting to
made up crap.


--
Sybrand Bakker, Senior Oracle DBA