Can OSX Server, et al, handle this website's load?

Question

I looked through this forum and the one on Xserve and couldn't find a topic like this.
The site is being converted from an obscure programming language to PHP/MySQL. In functionality, it will resemble a Craig's List for college students. Lots of database interaction. Very few graphics except for multiple small banner ad deliveries on each page. Lots of email interaction generated by a form at the site.
We're planning on picking up a new Xserve, dropping a couple of those 15k rpm drives the Apple Store sells into it, and boosting the RAM to 4gb (?).
What I'd like to know is the following:
1. Can someone give any real world numbers on the performance of OSX/Apache 2.2/MySQL and said hardware? Can the database handle 100k, 500k, 1M records? Are there general rules for how many page views per day that can be served? (Bandwidth should not be an issue...I believe we are allocated 1TB per month, and as I indicated, graphic content is low.)
2. If the server and software can handle X, would is the next logical step beyond X? I realize that this may never happen, but I do need to ask the question for my own peace of mind. In other words, how does one expand beyond the fastest hardware and what I perceive to be as the best software solution?
Right now the site is at zero, and everyone dreams of building the next MySpace or YouTube. If it flops or just never generates tons of traffic, I can figure out how to handle that. My concern is if it does go in the other direction, so, any tips/suggestions would certainly be welcomed. Thank you in advance.
Rob

Answer 1

> Can someone give any real world numbers on the performance of OSX/Apache 2.2/MySQL and said hardware
In most cases bandwidth will be your limiting factor more than CPU resource.
1TB might sound like a lot - and it is if you're doing mostly text-based content - but on a typical traffic sine-curve it equates to about 300kbps. Your server is more than capable of handling that without breaking a sweat (database schema notwithstanding).
All my servers are running multi-megabits per second and I still have room to grow.
1 million rows in a MySQL database is not large. I have MySQL databases using hundreds of millions of rows. Beware of your database schema (query optimization and indexes will make a BIG difference to performance).
The next logical step as far as scaling would be multiple front-end web servers talking to the database server. There are numerous solutions for load balancing traffic across multiple servers, depending on $$s and flexibility needs.
The biggest factor is going to be in choosing the language to write the site in. PHP isn't necessarily the best choice. You need to be very careful (and not an 'average' PHP programmer) to be able to eke the best performance out of a busy site (esp. when it comes to database interactions - you need to cache the data in the app rather than hitting the database for every single page hit).
There's nothing wrong with PHP - just be aware of its limitations and be prepared to deal with it (whether through code optimization or another language switch).