Earlier quoted context omitted.
FastMail's server is very standards compliant (except for some weird parts of LIST-EXTENDED that I haven't worked out how to do efficiently yet, so they're still broken in the upstream Cyrus IMAP server) And we're really blindingly fast for a lot of stuff, particularly if you're just downloading new email. We split every mailbox in to two sets of storage - SSD for messages less than 1 week old and lower than 1Mb in s…
I am curious what sort of storage solution Google is using to compare to this one..
There doesn't seem to be a published article that I can find on the exact internals, so I'm basing it off discussions on the protocol mailing lists.