> > > but for > > > heaven's sake, don't point your imapd at an NFS export. > > > > If I have more than one IMAP server (at least on different machines), > then > > how else do I point all IMAP servers to the mail spool beside > > NFS/GFS/AFS/etc? The connection from clients (SM, etc) to IMAP will > of > > course be regular IMAP connections/protocol. Eventually, we have our > eye > > on > > Perdition to help load balance IMAP connections. > > Regardless of what this guy says, your plan as you've outlined should > work and I only say should because I personally haven't tried storing > PHP session information on an NFS share before. There was some recent
Then how do you share your session data between more than one web server? You have session data in a database? > discussion about that on the list and I believe I saw the general > consensus to be that it would only fail under very unusual circumstances > (search the archives to verify though). The only real drawback is that > you are relying on round-robin DNS to load balance your machines. As I > mentioned earlier, if one machine fails, the RR will still send clients > to that now dead IP. That may be acceptable to you until you either > recover the machine or manually configure the remaining box to answer on > that IP as well. We use hardware layer4 switches in front of our systems > to perform automatic load balancing, health detection and failover. The > particular devices we use can maintain user session to one machine or > the other, negating the need to store the PHP session information on the > NFS box. This is essentially filling the role of the LVS and allows us > to provide very high service availability. Wow, must be nice to have that kind of money. :) How does a _switch_ know how to maintain session data for the _application_ layer in _front_ of a web server?? Sounds nice anyway. :) > As far as using Perdition, it wasn't really designed to be a load > balancer, at least when I last used it and wouldn't really be effective > at it. Your load balancing would be determined by WHO was logging in at > a particular time instead of how loaded a machine was. If all the users > assigned to server 1 were logged in an none assigned to server 2 you'd > have one box loaded and one completely idle. I would suggest that if you Wow, OK, thanks for clarifying. Hadn't really read up on it yet, but will certainly do so given what you say here. > get to the point where DNS load balancing isn't sufficient for your > needs you take the plunge and set up a Linux load balancer or purchase a > hardware switch that'll do it for you. Life is much easier that way =) > If you scale even further, separate your IMAP/SMTP/HTTP servers. If you > do that, you can grow the specific service that's being utilized the > most without having to rebuild all services for each machine. By that > time you should be bringing in enough money that cost wouldn't be > prohibitive. Yeah, that's the first thing on our list once we take the next step, so I'm glad to hear someone reaffirm it. Don't really like IMAP/SMTP/HTTP on the same server but we're stuck there for now. One possibility given the other response today is that maybe it's OK to run just one IMAP server on our NFS machine where the mail spool is. Our front-end HTTP/SMTP servers would reduce their load a bit, as long as we don't kill the NFS server.... Thanks again! > -- > Marc > > > > > ------------------------------------------------------- __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7393&alloc_id=16281&op=click -- squirrelmail-users mailing list Posting Guidelines: http://squirrelmail.org/wiki/wiki.php?MailingListPostingGuidelines List Address: [email protected] List Archives: http://news.gmane.org/thread.php?group=gmane.mail.squirrelmail.user List Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=2995 List Info: https://lists.sourceforge.net/lists/listinfo/squirrelmail-users
