Manuel Schneider pisze: > Hi, > > Paweł Tęcza schrieb, Am 16.09.2008 10:04: > >> Svetozar Mihailov pisze: > > >>> 2.2 I do not want to use load balancer because if load balancer dies >>> everything stop. I will implement monitoring (ping?) daemon, which will >>> add/remove servers to dns if some of them dies. Is there recomended >>> minimal TTL for dns records in this case? >> >> Yes, it's true that only one load balancer is not good idea. Hence, you >> should have two redundant load balancers or second backup load balancer >> on the alert.
Hello Manuel, > you could do "poor man's loadbalancing" by assigning several IP adresses > to the same virtual host name which acts as MX. > This way there is some kind of round robin (not a real load balancing) > among the mail servers. We were doing it exactly in that way before, but as I wrote in my previous post, it's not good solution for serious mail system because of Windows client hosts which piss on DNS TLL. We don't want to do any breaks for our users, if it's not necessary, so now we had to use real load-balancer to switch a traffic while administrator jobs. > We do this with a little "cluster" system for failover of different > services, including mail. > We run the primary and secondary nameservers on the both nodes which > advertise their IP adresses with TTL 60. So when a host goes down the > nameserver is also down and the IP adress isn't advertised any more. > That's not very sophisticated, but cheap... For what the folks want to > pay for it it does a great job. Our university mail system should be available for users by 24 hours per day and 365 days per year, so we have separated and redundant name servers, load-balancers, front-ends with SMTP/POP3/IMAP/webmail/anti-virus servers and anti-spam nodes and storages. All runs on Linux/OpenVZ/free software based platform. As you can see it's not a little system :) Have a nice day, Pawel ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
