Hi all - I'm just looking ahead now and trying to see how well dbmail will scale with larger deployments.
We're currently running dbmail with: - Dual Xeon 2.4G processors / SCSI Disks - MySQL/InnoDB - roughly 90k mailboxes - 100G of mail data - alias selection offloaded to smtp servers (we don't use aliases table we deliver straight to userid) - Load average between 0.4 and 2.5 on a dual processor machine, averaging at around the .8 mark (so say 50% load) We have 4 machines handling SMTP/Virus/Spam filtering and then handing it to dbmail-smtp for delviery, and 3 machines doing POP/IMAP -- all of which are light-moderate loaded. I've been posed the question by management lately -- how would dbmail scale if we wanted to offer say 3 Million mailboxes, rather than just the current limit I see of 100-200k mailboxes using my current setup? Ideas that spring to mind are: Clustered databases ------------------- Oracle or some database with multiple write masters and cluser-wide locking for writes springs to mind. I understand there is problems with MySQL one-way replication and directing all writes to a master server, but reads from multiple slaves - due to write-locking not being supported thus the slave getting out of sync with the master, etc. I scanned the list again recently but couldn't find any obvious posts with solutions for this. Last minute addition >> I notice SAP DB is now MySQL MaxDB and is available. Anyone looked at this as a viable backend for dbmail? Can't for the life of me find the details on replication support/etc on the site... Partitioned databases --------------------- The old customea A-E on database server 1, F-L on database server 2, etc. This would seem to do the trick, although with dbmail it may be user_idnr 1-50,000 on DB1, 50,001-100,000 on DB2 I guess, with some sort of central mailbox -> store index table. I haven't looked at the code for 2.0 recently, but from memory 1.x maintained a persistent connection with the mailstore, thus this could be quite bad if there were say 100 database servers. I'm not sure what the overhead would be for connection setup/teardown if doing dynamic connections to different servers. Any other ideas? (even if not likely to be implemented officially by dbmail -- may code our own variation if needed). Cheers, Mark Mackay.
