Very Computer

 I just installed iplanet enterprise web server.  Our plan is to have
multiple instances running on different ports.  All the instances will serve
the same documents.  Are there software packages for load balancing between
these instances?  Do I get better performance running multiple instance on
different ports?

I realize that this may not be the right group to ask this question.  Are
there iplanet / web server related newsgroups?

use the news server : secnews.netscape.com
use a secure connection, you should be able to get a lot of info from the
iplanet/netscape
web server newsgroups.

--

__________________________________________________________________

Scott Lawson
Systems Manager
Department Of Information Services
St. George's Hospital Medical School
Tooting
London SW17 0RE
UK

P: 44 (0)208 725 2896
F: 44 (0)208 725 3583

http://www.sghms.ac.uk

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  Are you going to run all of those on the same physical NIC?  
  Or some reason why you wouldn't just use IP aliasing to add
  more IP addresses to the NIC and have the server use the
  standard port on the IP Aliased interfaces?  

  Whether you get better performance is highly dependent on
  more things than you've described.      Unless you expect
  to be getting a LOT of traffic, don't see how running multiple
  servers would gain any performance as opposed to just increasing
  the server threads.  

  And if you have multiple NIC's, just run the IP's over them
  and use port 80.  

  The one area that bites a bit with iplanet enterprise is the
  search engine.  If you have multiple logical servers, even
  if they are indexing and serving the same set of files, you
  get multiple instances of the verity database collections.
  [which may or may not be what you desire....]

  For real performance, running iPlanet on multiple physical
  servers using some of the web redirector products allows
  a single URL to be handled by any number of servers.  E.g.
  Alteon etc.

  iPlanet has a website, pretty sure it is linked off www.sun.com,
  but if not, the knowledge base on www.iplanet.com is a good
  starter.

This would be a very awkward way of achieving something that iPlanet
does naturally.  iPlanet web server is both multiprocess and
multithreaded.  The only reason you should install multiple server
instances would be because the instances serve different content.

I'd suggest going to http://docs.iplanet.com and doing a search using
"tuning" - there's a webserver tuning guide online that will give you
lots of helpful tips.

Additionally the the iplanet newsgroup for netscape enterprise server  
is at:  

Regards
Tim

I was just told today that one of the thoughts behind running multiple Web
Server instances on the same server with load balancing software is to avoid
outage if one of the instances has problem (instance hang, instance
encountered software bugs/errors, instance  brought down unintensionally,
etc.).   Does this make more sense?

Thanks for everybody's input as I am new to this.

It makes some sense, but have you heard what happened about 40
seconds after the launch of the first Ariane 5 rocket on June 4,
1996?  The rocket veered off course and exploded.  The reason
this happened is that one of its on-board computers had a
software failure.  So, the rocket reverted to a backup computer
which was there specifically in case that computer failed.  Did
that help?  No, because the backup computer was running the same
software as the primary computer, so it failed in the same way.

I'm not saying that this kind of thing will happen to you
if you run a web server on two ports, but I am suggesting
that it's easy to overestimate the gain in reliability you
might get from running two instances of the same software.

  - Logan
--
"In order to be prepared to hope in what does not deceive,
 we must first lose hope in everything that deceives."

                                          Georges Bernanos

  If that is the goal, it is the wrong way to achieve it.  
  If one of the instances wedges a good one, the odds of the
  others continuing to serve aren't that good.   There is
  also considerable overhead in doing this that really gains
  nothing more than a false warm fuzzy.  

  If non-stop service is the goal, you will want multiple
  systems with web redirector hardware and or software.
  You can drop the files on a multi-access SAN or a small
  cluster of network file servers.  

  If this is a web site that you plan to rely on for income,
  it is a false economy not to hire an iPlanet knowledgeable
  consultant to help come up with a few reasonably good
  layouts that will actually work.  

Thank you very much for all the input. This will be an intranet site running
on a powerful server.  It'll be part of an EAI architecture.  While $ is not
the objective here, it is a critical piece.  I guess we'll rethink the
approach.