What makes you think that you need Xserves to support a network of Macs? You do not. You could use just about any server for that purpose. I bet that Apple has way more data on this subject-matter than anyone on this discussion has. And I bet that data shows that
Supporting a large deployment of Macs using Open Directory means you *need* an Apple Mac Server. Managing MCX without OSX Server (and therefore Apple Hardware) is incredibly complicated and would likely require a full-time xml guy just to sit there maintaining users et al..
So that means you can only use Apple Hardware... Apple Servers.
You suggest 3 x Mac Mini is as good as 1 x Xserve. But for most services, Apple state a Mac Mini can only handle around 10% of the clients that a XServe or Mac Pro can handle (read the deprication PDF for more info). You can't just split a service like iCal server or Mail across three discrete servers, wave a magic wand and call it 'redundancy'. First off it wouldn't work and even if it did, a single failure would kill your service.
So that leaves the Mac Pro. Apple are selling it as 'hey, its cheaper and more powerful!'
But that's because it isn't a server, so costs less to manufacturer, and it's not just the LOM and PSU that people keep talking about: -
- No redundant PSU.
- No LOM.
- Inefficient Form Factor is unsuitable for server rooms.
- Less Fan redundancy and air flow.
- Less monitoring capabilities.
- Uses economy hard drives (Xserve is supplied with WD RE3/4 drives with double MTBF figures).
I sympathise that Apple don't sell many Xserves, and that they make a loss on each and everyone I wouldn't be surprised. But it's a little like HP selling printers; They sell them below cost and make their money on the toner. In this case, Apple make money on the Macs which are supported in the Enterprise and .Edu environment by their Xserves.
Guess we need to go buy an iServer-Room for our mac-pro servers.
:-( unhappy-mac