Whilst setting up a Rails app for one of our clients I’ve been getting 503 errors occasionally when browsing the site. It seems to occur whenever the fastcgi process has been dormant for a while, and presumably killed of by mod_fcgid, and very occasionally at other times. A bit of googling showed that this seems to be a known issue with older copies of fcgid - unfortunately the server in question is running Ubuntu Dapper Drake, and so v1.07 of fcgid with no backport available.
We’re running other rails apps on a Debian Etch box with a marginally newer fcgid v1.10 with no problems so I decided build my own backport of fcgid. My first attempt was with the copy that comes with Hardy (v2.2 I think) since that’s what my laptops running, this didn’t work though because of dependencies that couldn’t be satisfied by Dapper. In then end I backported the copy from Edgy Eft since thats 1.10, same as debian, and so far that seems to be working fine. So if your getting the same error it might be worth installing my backported libapache2-mod-fcgid deb.