Apache/PHP and MySQL on separate servers
I currently run a setup (at a private office) with an LVS box load balancing two 2.4GHz Apache/PHP boxes, both of which connect to a 2GHz MySQL box which has a common database used by the Apache/PHP boxes.
In other words, it's a simple cluster. The LVS is set up for load balancing and it does a heartbeat against the Apache/PHP boxes so if I take one of them down, it sends all traffic to the other. The scripts running on the Apache/PHP boxes are stateless (all state is in the MySQL box). I don't have redundancy at the MySQL or LVS point in the architecture -- I could add another LVS box for failover at that level. Clustering MySQL is trickier, I do have a mirrored RAID setup on that box though.
I am running out of bandwidth where this is currently hosted and looking to move it to a host like Rackshack. I can't have a VLAN there so I'm looking at zoneedit.com's load balancing/failover DNS server as a proxy for the LVS. I believe Rackshack's bandwidth limits are plenty high enough per box to allow me to handle the between-box MySQL traffic... but the question is, will the performance of MySQL from one box to another at a setup like Rackshack, where I am using public IP addresses to get to the MySQL box, be adequate.
Seems like it should because an IP is an IP whether public or VLAN, but I wonder if anyone has any experience running heavy PHP/MySQL sites with non-VLAN interconnect between the PHP and MySQL boxes?
Thanks for sharing any real-world experiences!
Rowland
