Am Mon, 2003-10-06 um 16.51 schrieb Theodore Knab: Most things seem quite good - anyway a few questions/comments:
> Since you are familiar with LVS, you should have no problem setting 2 > [redundant] LVS systems up. You could balance the load between 10-20 > IMAP servers. I would also suggest LVS as I stated in my other posting - use keepalived to get your balancers redundant. But 10-20 IMAP server (each of them dual Xeon)? Seems "a little bit" much... In my experience the POP/IMAP server are those machines with the least load. The need some I/O so you definitely want to use GBit for accessing the data via network. > You might also be able to use the same 2 LVS systems to balance your > load between the Web-mail servers. > > <Crude Diagram> > > [Firewall] > | > | > | > [LVS1]----[LVS2] > | | > [Fiber Only Switch] > | Why fiber-only? Gbit copper is MUCH cheaper and as all server are probably side-by-side in a few racks I don't see we you would need fiber interconnects. > Estimated Minimums needed for 500,000+ Email Users > -------------------------- > 10 IMAP servers [Courier IMAP 1 [Dual Xeon 1GHz] server /200 active users] > w/ XFS filesystem and Debian Stable As said before - 10 seem a little bit much. You can add more server to your pool anyway. As for the FS: XFS/ReiserFS/ext3 shouldn't matter as all files will be stored on a SAN/NAS anyway. > 20 Webmail Servers [Squirrel-mail 1 [Dual Xeon 1Ghz] server /100 active users] > w/ XFS filesystem and Debian Stable If you want to provide webmail too... 20 Dual-Xeon seem a little much again as probably not all users will use HTTP to access their mail if they can use POP/IMAP instead. > 2 Databases Servers for authentication either [Mysql or OpenLDAP] > w/ XFS filesystem and Debian Stable Redundant setup or a clustered approach with multiple read-only and one master-server if the DB queries become too intensive. > 2-4 MX Gateways running either Exim or Postfix MTA and SPAMD with > w/ XFS filesystem and Debian Stable Amivisd Now that's IMHO not enough for 500k user... If you do spam-filtering, virus-scanning and maybe even filtering (trough procmail or something else) on your MX you'll definitely need either some quite powerful machines or some more smaller ones. > 2 [Fiber Channel] SAN Volumes for [MAIL storage] redundancy. > </Crude Diagram> Or NAS or even "self-build" NFS server. If you want to access your FC SAN from all your MX and POP/IMAP server it could become "a little bit" expensive if you consider the bunch of FC-HBA and FC-Switches you'll need... Anyway, as I said in my other post: Hardware dimensioning is something which will definitely consume quite a bit of time as you don't want to have any bottlenecks nor spend huge amounts of money on something you don't need. Maybe talk a few hours with someone (real-life, not ML) who has build something similar (not necessarily a mail-cluster, but something with huge amounts of data on a network) as they probably know most of the pitfalls first-hand :-) best regards, Markus -- Markus Oswald <[EMAIL PROTECTED]> \ Unix and Network Administration Graz, AUSTRIA \ High Availability / Cluster Mobile: +43 676 6485415 \ System Consulting Fax: +43 316 428896 \ Web Development -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
