So mail /home & auth are to be split. The major obstacle to this was the fact that mail requires .procmailrc, .forward and the like. These have to be available in the users home directory and we dont want the mail server to be reliant on an nfs mount. If it is, no improvement in network availablity is made since if the nfs server goes down the mailserver hangs on nfs blocking.
So the mail is to be written to a local disk on the mailserver using [maildir] (have wanted to move over to this for a while, see below) format. each user will have their own homedir with maildir directory on this disk. this homedir will hold all the conf files and whatnot for procmail, spamassisin and anything else the users want. This disk will be mounted on the login machines. Each user's directory is then symlinked into their home directory so they can edit they're config. They'll also be able to get at their mail this way (mutt and [modern Emacsen] have Maildir support) but just using imap will be easier.
A tutorial will be written up on all this.
Of course people arent going to migrate their mail setup immediately so there's going to have to be a grace period for people to test the new system. Scripts/tutorial will also have to be written to migrate old mail over to maildir.
Initially mail auth and /home will be on hex(the new elsevier box) using the same setup as the current although service based ssl certs will have to be issued.
Then the new mail setup will be set up on another machine(probably current holly). a backup ldap set up as well so if hex goes down mail will still work. an mx record for testing.skynet.ie to point to this machine set up. If people want to use this new setup they put email@example.com in their .forward after setting up their procmail scripts etc.
Maildir format is nice. With procmail filters all your mail can be stored in IMAP folders so that it can be available with any email client from anywhere, instead of logging into skynet to get at your folders.
Diamond: I don't see any benefit to giving nfs access to the maildir. Config file access is more than enough, imap provides everything else much more gracefully.