Building Enterprise level application using Codeigniter

[eluser]Nikhil Vijayan[/eluser]
I am planning to use Codeigniter for an enterprise level web application. which will have 2-3 million visitors per month .. the goal is to serve maximum users with minimal server resources..

So do u guys have any suggestions ,advice for me ?

Do u think its better NOT to use any frameworks ?

What about Active record , etc .. Does disabling Active record improve performance ? if yes why ? we are using mysql as DB so i dont need other db drivers so does disabling them help improve performance ? ...

Let me know what your experience using codeigniter is..

Between i will be also using matchbox for modular separation.

Looking forward to hear from u all...

[eluser]nmweb[/eluser]
Taking away AR and writing all queries by hand will certainly boost performance. Stripping CI on other points might also be beneficial.

[eluser]Yash[/eluser]
MVC framework

Advantage
1: Huge libraries collection
2: Complete Database Support
3: easily manageable code.
and lots more..

disadvantage
1: take time to understand each library
2: lots n lots feature may confuse u..

and so on ...

[eluser]Nikhil Vijayan[/eluser]
Thanks for your response..

@mmweb

"Stripping CI on other points " ...

Can u specify them .. ?

[eluser]louis w[/eluser]
#1 Advice: Cache

I would even think about writing your own caching library so that you can cache pieces of a page instead of just the final output. If you are really expecting that much traffic you need to do as much work as you can to reduce the number of requests that need to be processed.

[eluser]RaZoR LeGaCy[/eluser]
You can use Zend_Cache to cache small chunks of code for longer periods then the final output.
Ex. Final output cache can be set to 20min and the Zend chunk cache can be set to 1 hour.

[eluser]louis w[/eluser]
For a project I have been working on, I cache some pieces for 24 hours. Since the cache is cleared if you save an item, there is no worry of it getting stale.

Sometimes I have even set up a cron job to regenerate the cache during the night so that a user never has to (when they make the first fresh request to it).

[eluser]RaZoR LeGaCy[/eluser]
What do you mean by "when they save an item"?

[eluser]louis w[/eluser]
The project that I am speaking of is a cms. So whenever you save a page or a page which is linked to another page in the admin then I clear all respective cache records.

Additionally, for something like a user-gen site, whenever a user updates his/her profile you clear their profile's cache record (and maybe the directory too).

Whenever a request is made to an item if a cache record doesn't exist, the system creates one for subsequent requests.

[eluser]parrots[/eluser]
I've found this very helpful: Optimizing and Scaling your CodeIgniter Application - with Benchmarks!. Doesn't go over everything like not using AR, but gives some really good tips on caching (both within CI and php caching tools).