I've got some heartburn about upas/fs. Seems our user base is growing larger than main memories of our imap servers. Anyone have any ideas to keep systems from running out of memory? Anyone using something that virtual memory to keep the mail boxes?
Plan9ports has a new upas/fs (called mailfs for now, and in $PLAN9/src/cmd/upas/nfs) with only an IMAP back end, but it demand loads from the IMAP server. I structured it so that it should not be hard to add a module for reading local mailboxes too; those could be loaded on demand as well. Also, the existence of the on-demand loading means one can treat memory as a cache, tossing out messages as memory fills and reloading them as needed. One could even keep a local disk cache of message pieces instead of requerying a remote mailbox. The hard part of adding local mailbox support should be finding your place when the mailbox has changed underfoot, not any structural part of the fs. Russ
