How do I scale a web application with HostingRails.com?

How can I tell if I need to start with a shared, VPS, or a dedicated plan?

One of the first things to determine is where your budget allows you to start out - shared (~$3/mo and up), VPS (~$20/mo and up), or dedicated ($250/mo and up). The advantages of shared are that its cheap and we manage it for you, but there can occasionally be slowing because you're sharing a Single Server with multiple clients (we do our absolute best to keep this alive and running smoothly). The advantages of VPS plans are that you have dedicated memory, databases, and the only disadvantage is that it share CPU with other VPSs on a node. If a lot of CPU power is needed, then dedicated is the way to go.

Are PHP and Perl apps using mod_php/mod_perl really only $3/mo?

Yes, if you don't use a lot of bandwidth or disk space the pay-as-you-go plan stays right near $3/mo.

What is the difference between using the Pay-as-you-go plan and the Basic-Platinum plan?

The Pay-as-you-go plan is charged daily and billed monthly. You can set a monthly budget and be emailed every day your plan is moving in a direction that exceeds your budget (so you can scale back). The Basic-Platinum plans are fixed prices and are billed yearly and only allow a finite number of application servers (see above chart). A Professional plan allows one mongrel or Passenger app. A Business plan allows two of either, etc... If you need more memory, you need to upgrade through your account center.

How do I upgrade from a shared to a VPS?

You'll need to first signup for the VPS plan, copy over your files/dbs and other configurations (we can do this for you for a $50 one-time charge). Then after you switch your DNS to your VPS (new IP) and close down your shared account, we'll apply the remaining credit over to the VPS plan.

How do I scale up from one to two or more VPS/Dedicated plans

This switch enters you into the "cloud" and requires central dynamic asset storage (we recommend Amazon's S3), database Master/Slave replication (there is a plugin called Masochism to handle Rails read/writes), and round-robin DNS/load balancing (we recommend NginX or Apache). Our support staff would be happy to then help you scale further. The process is roughly as shown in the above chart.