The above description is a bit idealized. Keeping everything in macid limits you to how much RAM you can afford, + and even if you can afford a lot (16GB in the amazon cloud costs \$576/month) there's no guarantee that you won't + max that out if your application has a lot of data. + (See the stress test chapter for more caveats.) + The HAppS developers have promised a version of HAppS that will make it easy to share ram across computers + with a technique called sharding, but this hasn't been released in a way that inspires confidence in me + (on hackage, sufficient documentation), + and to be honest I don't really understand how it is supposed to work even in theory. + But what is realistic is to write an alpha version of an application without a database access layer, + and then add persistent hard drive storage (probably database, but could also be flat files or name your poison) + outside of macid when it becomes necessary. Most web projects do not get to a size where this is necessary, + so arguably coding in a database from a start is a form of insidious premature optimization, if you buy + the argument that databases have overhead. +