I'm trying to get an overview of how i would go about creating a load balanced web server setup. Setting up the actual load balancer and adding two or more web servers seems fair enough. However, I can't decide what the best setup for files would be.
The web servers will be running a CMS system (in this case Drupal). There might be files uploaded by users which relates to content, and this should be accessible to all web servers. Now, I was thinking of simply having a designated file server and mount a file directory on each web server so that the various web servers could access these "shared" files.
However, would this solution be a bottleneck if we're talking about 4-5 servers? I'd think the mounting would be done over SSH.
All help highly appreciated!
Update (January 15, 2013)
I decided to go with a combination of Csync2 and Lsyncd. I then set up two servers which acts as mirrors. Lsyncd listens for changes in certain directories (and their subdirectories) and invokes Csync2 which takes care of synchronizing files to the other server. If you're interested in knowing more, have a look at this tutorial.
Best Answer
Before I moved to the CDN I had a web farm of about 20 servers. I started with NFS until I hit a bug in the linux kernel about 3 years back that caused an issue with not mounting the volume and it wasn't failing over correctly.
I then created an rsync script that would sync the dir's every 5 minutes to each image server. This wasn't ideal but it worked and I didn't have any issues with it.
The next step I switched to lsyncd which uses inotify to monitor a directory and when a file is changed it spawns a process to sync that file. By default that's rsync. That solution was solid and if not for the economy of a CDN I would have continued with that.
Lsyncd: http://code.google.com/p/lsyncd/
Hope that helps.