[OpenAFS] Replica sites

[Russ Allbery]

ed <ed@ednevitible.co.uk> writes:

> Well, I like the features of AFS, however, the scenario is this, I have
> a single mail server for webmail, IMAP maildirs, spam filtering, virus
> scanning etc.

> This mailbox is getting loaded, primarily through IMAP access. I need to
> spread the IMAP folders out, so that one of 5 (more or less) front line
> mail servers can talk to one of a number of file servers.

> What software would your recommend for this?

While there are a few people who have had luck with smaller sites, the
common wisdom is that mail delivery into AFS will make you sad, if not
sooner than eventually.  Mail delivery does a lot of small file writes,
which is not AFS's best performance point, and AFS also has some
limitations in the number of files that can be put into a single directory
that are likely to cause problems for you if you really do have over a
million files in one directory.  (I'd worry about performance for
directory lookups there as well; AFS isn't as sophisticated as modern
local file systems in that regard.)

Personally, for an IMAP server, I would declare IMAP as the one and only
access mechanism to the data and then use local RAID storage on the
individual IMAP servers.  That's what we do at Stanford.

-- 
Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>