From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: Date: Fri, 9 Feb 2007 10:42:33 -0500 From: "Russ Cox" To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu> Subject: Re: [9fans] Anyone working on new upas/fs? In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: Topicbox-Message-UUID: 0fad3bc8-ead2-11e9-9d60-3106f5b1d025 > 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