What are hardware requirements for a cloud hosted PostGIS & GeoServer?

I have been playing with a local installation of PostGIS & GeoServer. I would like to move my work online now to share it with several collaborators.

The proof of the concept map will consist of simple WMS and WFS services mapped through OpenLayers and GeoExt. It will be based on a map of ~3000 administrative units. Initially it needs to serve several people only. From then we will be working on polishing final view and functionality of the application.

There have been several suggestions made under answers to this question. For example, Nicklas is running his site on 512MB Linode (I think...).

I was thinking about using Ubuntu Server on cloud VPS, most likely hosted on rackspace.

My question: what would be the minimal server size I would need to use to start playing with this data online? There are few of them available. Once we decide to open the service to public rackspace promises seamless way of scaling up the service, so I would like to know what bare minimum RAM I need to start with.

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Update 1: Similar discussion on GeoServer forum.

Update 2: Useful tutorials on setting up stack on AWS micro instance using Ubuntu and CentOS.

Answer

It really depends on the size of the datasets you are talking about and the complexity of your queries. I for example run pretty happily on a GoGrid server /PostGIS / Windows 2008 (32-bit) running IIS, a mix of PHP/.NET homegrown webservices with 2GIG ram/ dual core. The main spatial table I query has about 6 million records I think of mostly California data. I do fairly complex spatial queries with that on the fly intersections/transformations, distance checks with geometries some of which are fairly big. They go from single points to large polygons with 8000-10000 someodd points.

Given that Windows tends to be a hog as far as RAM with all that extra junk running. I imagine you can do pretty well on 1G ubuntu (and possibly decently on 512 MB). I'm not sure how much of a hog GeoServer is though but I imagine it can't be much worse than what I'm running.

Forgot to say. You should run with PostGIS 1.5/Geos 3.2. The performance is much better than older versions particular for neighbor queries involving ST_DWithin and so forth (thanks to Nicklas :))