I'm changing the way that our DHCP/DNS stuff works at work. Currently we've got 3 DNS servers, and a DHCP box. All of them are VMs.
There's a circular dependency where stuff booting requires NFS, which requires DNS. So when we reboot stuff, things might come back subtly broken until the DNS is up, and we restart some services.
What I want to do is have a few low power servers, probably dual core Atoms or similar, running from SSDs, so that they boot damn fast. I want to make the whole thing boot as near to instantaneously as possible.
Ideally I'd like to use Ubuntu 11.10, or Debian 6 as the OS. I'm not interested in Gentoo or compiling my own kernel. This needs to be reasonably supportable by myself.
Other than SSD drives, what other optimization steps can I take to improve boot speed?