I took the “always on application” and ran through some numbers this evening. I was curious – with the hosting options available today, what would it cost someone to run an “always on” application.
The way I’m thinking about it, GAE probably isn’t the right thing. They don’t easily let you run repeated cron jobs, making an agent style application (i.e. proactive, rather than reactive) not quite a good fit. So what would be? A VM. Sure, you could slice it down farther and get a slicehost style thing – they’re excellent, but many of them have restrictions about “long running processes” – and that is exactly what I want.
So what’s it take to run a VM? There’s an interesting question. The cheapest I found was Rackspace – that offered a 256MB Linux hosting solution for $10/mo. Linode starts at 512MB for $19.95. Of course you need to at least make a vague attempt to compare to an EC2 instance. The always on really bites you there – the cheapest I could get my numbers was around $6/mo (a single micro instance, 1 yr commitment – minimal to no bandwidth).
I have to wonder – how well would something like that be received? Say you could offer a private agent/proxy service for $10/mo. I suspect you could get it cheaper – the compute needed for this kind of service would seem to smaller than the minimum you can purchase as a slice of compute. But people aren’t generally buying like this – at least not today.
I think most folks who have a desire for something like this would be more likely to have a desktop computer at home they could dedicate to leaving on. That’s assuming they have an internet service to their house too – so the real cost is more than the hosted compute, but since people often have it anyway… I’m guessing they’d be more likely to want to just use it.
The closest to paying as you go for an application gets to the Platform as a Service – Google App Engine or Microsoft Azure. Frankly neither of which I particularly want because they both represent a sort of technology lock in. In development now is OpenStack – Rackspace & NASA doing some of that base line commoditization work to drive down the costs of running small VM slices. We’re already on the sweet side of Moore’s Law for the commoditization of compute resources – it’s just a few more years until it’s a complete no brainer.