I've been using slicehost for dev server for almost a year now. Since my 1 year deal is up, I decided to switch to their affiliate mosso. I really like slicehost, but Mosso "cloud servers" seem a good fit for a server that goes through spurts of development and use followed by weeks of non-use. So now, I can keep it as a 256MB instance at about $10/month and update to a larger instance when doing real dev.
I built it today as a 1024MB instance -- installed all my usual stuff, and updated my build script for ubuntu. That's here.
The machine I'm on is extremely fast, normally I set GDAL building and leave, but it finished before I had a chance. After all was built, I resized it to a 256MB server -- that took 12minutes, but my instance was accessible for at least 10 of those.
After that, I log right back in and all works fine. On this dev server, I have to run PHP (at least I dont have to code in it). I've been getting tired of having to use apache's mpm-prefork because ubuntu won't let me have php and mpm-worker. (For more from someone who actually knows what they are talking about, Graham Dumpleton, the author of mod_wsgi, has a good write up here.) So, every apache process takes up a good chunk of the available memory and things are sloooow. Even just running trac, it starts swapping.
I found a good post for using fcgi for php and followed it blindly and all works!
Using worker_mpm, Trac (via mod_wsgi) is so fast I doubled checked to make sure my instance was still at 256MB. After setting ThreadStackSize to 1.5MB trac takes up only 16% of the available memory. The relevant bits of my apache config look like:
# i keep this fairly high for serving image tiles
# from mapserver
# default is 8 per child process, only use 1.5MB
AddHandler fcgid-script .php
FCGIWrapper /usr/lib/cgi-bin/php5 .php
and then in 000-default, i added +ExecCGI to the DocumentRoot Directory Options.
If any of that config is not sane, let me know.
I should say that I have no idea how PHP will do under fast-cgi, if it uses more memory, or not, or if it will have any problems, on quick look, everything seems ok.
Apparently, you can also use mpm-worker with php if you build php from source. Since using fcgi worked so easily, I didn't try that.