On Tue, 2005-10-04 at 14:21 -0500, Les Mikesell wrote: > On Tue, 2005-10-04 at 07:03, David Hollis wrote: > > For my company, I've setup a mail/groupware environment that uses > > Postfix, OpenLDAP, Postgres, Apache, etc and am now looking at ways to > > make it a more redundant arrangement. All of the components have > > methods to help me with the lone exception of the backend mail storage > > for the end users. Ultimately, I am wanting to have systems at > > different geographic locations, not even on the same network, ideally > > with users able to access any of them at anytime and be able to do their > > thing. The users mail storage is in Maildir format which seems like it > > will help any replication type scenario. I can't just NFS mount the > > mail directories, because then my NFS server becomes my single point of > > failure. > > One of the points of using the maildir format when it was invented was > that it worked on NFS, and back then the way to make NFS reliable was > to run it on an appliance like the NetApp filer, and if a single unit > wasn't reliable enough you could get them with remote mirroring. These > days you might be able to find something cheaper, but the same concept > should work. ---- that may be but I would definitely check with other users of the same mail delivery agent to find out how they are handling backup and redundancy so you get their wisdom instead of surprises. ---- > > > Do things like GFS work to handle this? If so, do they > > operate across slow links (not talking dial-up here, but general > > Internet cable/DSL type links) > > Is GFS production-ready? ---- I don't know - if you look at http://www.redhat.com/software/rha/gfs/ you would get the impression that Red Hat thinks so ---- > > > If it helps, our total mail volume is not that tremendous so completely > > instantaneous replication isn't totally necessary, but I would want > > fairly quick convergence (say 30 minutes or less). > > You could cycle through the maildir directories with rsync to a > failover location pretty quickly - or even take everything in > home directories if it doesn't change too much. However you > need something different if you expect to access the different > copies at the same time and propagate changes both ways. ---- I guess it all depends upon one's expectations of HA and the reality of 'pretty quickly' Craig -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
