Hello Ryan,
The way I achieve this through dbmail is by using a replica mysql cluster as a back-end database
In practical terms you set up the 2 sites each with a mysql DB and configure them for mutual replication. On top you have 1 dbmail instance deployed at each site that points to its respective database.
In my case I have also a Linux Virtual Server load balancer in front of the cluster with a Virtual IP used by my clients to connect to dbmail.
In this manner you can also periodically shutdown one of the 2 replicas. Once the replica is brought back on-line mysql automatically resumes replication.
I hope this helps, Mauro On 21/09/18 04:26, Ryan Beethe wrote:
I am currently operating a small mail server (postfix + dovecot) but I have experienced a couple of ISP issues recently and would like to improve the availability of my server by operating a second server at a separate physical site (the sites I have available are separated by a 60ms ping). I am new to the world of high availability, but given my resources and constraints, an "active/passive" configuration seems to be my best option, where I have a primary server that is up most of the time and I can use pacemaker to switch from one to the other for failovers. I think I could get away with not using a distributed file system if I were to switch from dovecot to dbmail. I definitely need the distributed database, so avoid also using a distributed file system seems like a way to keep my architecture as simple as possible (but please correct me if I am wrong). For doing geo-replication, I have read that galera supports georeplication. But my gut sense is that galera's synchronous protocol in combination with my ping time would make anything that needed to write to the database a lot (like dbmail) prohibitively slow. Does anybody know if that is the case or not? Also, I read that auto_increment columns with the galera plugin are guaranteed to be unique, but not guaranteed to be sequential. Would that break dbmail? My other option would be a master-master synchronization between the two databases. I know people on this mailing list have been doing that for a while, because I read about that setup on this mailing list as far back as 2006. But (noob question alert), since the master-master database sync is asynchronous, doesn't that run the risk of data loss or corruption from the very latest data if a server crashes? Has that ever happened to any of you with dbmail, and what is the recover process like? Ryan _______________________________________________ DBmail mailing list DBmail@dbmail.org http://lists.nfg.nl/mailman/listinfo/dbmail
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