OK, seeing as I now have my MSDN version of MOSS 2007 I've scrubbed a load of rubbish of the disks in my lab and gone for a multi-server build to see how the components will stack up in something approaching a production environment.

In this instance I have a "real" SQL 2005 server and two virtual MOSS servers, one to be an Application Server and one to be a front-end web server purely to render content to the end user. The build, thus far, has gone remarkably simply but I've just hit a bit of an intellectual brick-wall while trying to configure the services on the farm.

Having to start the WSS Search service on the application server purely to enable searching of help content seems a little wierd but I can live with it.

The really confusing thing (or perhaps its just that I'm a bear of very little brain) seems to be the on-screen text accompanying the page to configure the Office SharePoint Server Search Service Settings.

The way I had envisaged it was that in my two-server configuration I would be able to run most of the services on my Application Server (in an SSP environment) leaving the front-end web server to just render content and consume such services as were appropriate.

However it doesn't look as though it works like that. At the top of the page you define whether your App server is going to index content and/or handle search queries. OK - I want mine to do both. This then brings up a number of other options further down the page. All th estuff about accounts is generic and understandable until you get to the last section about "Web Front End and Crawling"

From this it would appear that for your Application Server to act as a crawler (i.e. carry out the indexing function) it also has to be defined as a front-end web server. Err - why ? Surely the indexer creates indexes and then, if necessary, propagates its index to one of the search servers. I can't see any logic to why the indexer needs to be a front-end web server.

Nonetheless this seems to be mandatory, and so moving on we are then presented with a series of conditions for making the server dedicated or not. The help text says:

"Use this option to specify a dedicated web front end for crawling. Crawling through a dedicated web front end will reduce the impact of crawling on the other web front ends in the farm.

If your index server is not running other shared services, it is recommended to enable the web front end role on this computer and use it as the dedicated web front end for crawling."

OK - so taking those two together it seems to be saying that a dedicated web front end for crawling is a Good Thing and that in an ideal world you have one server which is working purely as an indexer and not running any other services. OK - not too far from the 2003 model (except that there the indexing server typically acted as the job server too)

But...

If your index server is also running the Excel Calculation service or other shared services, select no dedicated web front end for crawling. Otherwise, these services may not work as expected.

So unless you have the luxury of a dedicated application server to act as an indexer then this suggests that you *must not* dedicate it, but instead (by inferrence) allow the crawling service to be shared across all your front-end web servers.

But surely this completely breaks the notion of having a three-tier web / application / database architecture for MOSS 2007. If I set this up the way it seems to be suggesting, I will have the crawling/indexing service running on both my front-end web server and my application server, the search service running only on my application server, and any other applications (profiles, excel services etc) also running on the application server.

It seems, somehow, counter-intuitive to force me to run the indexing service on a front-end web server which I *wanted* to just use for serving content to end users. If one was to be forced to run any applications there, wouldn't it be more logical to force the "search" rather than the "indexing" application?

As always, helpful hints and suggestions (including "Andy - you plonker, you've completely got hold of the wrong end of the stick") gratefully received. :)