>I want to ask if imail 6 support Load balancing or just clustering.
>If it support load balancing , how can I implement that .
>Plz help ASAP while I must decide to build a new system.
Waleed,
If you are interested in load balancing or clustering, I assume you
are planning for either a BIG load (100' of 1000's of msgs) and/or
fail-over reliability.
In either case, I suggest you not approach the pb thinking "1 Imail
box is great, 5 identical Imail boxes are greater".
Rather, divide the total pb into functional boxes with an eye to the
mail protocols and how to allot them to non-identical, "assymmetric" boxes.
Mailbox server + web mail server + pop3 server + SMTP AUTH are, in
Imail6, indivisibly required to be on one Imail box.
The only load-sharing Imail supports natively is Imail's proprietary
peering for distributing incoming mail for a domain over 2 or more
Imail boxes that share (not duplicate) the mail accounts/mailbox
storage. And each peer server has its own private user base, it does
not share a single external user base. Each Imail user will have to
know which Imail server holds his account + mailbox and use that info
to set up his POP3 server and SMTP (AUTH) outbound server. ie, each
Imail server is independent of the other Imail servers, they don't
share a total single load accounts base, the each have their own,
separate account database.
For webmail, there is some relief to the above, by using HTTP
redirection, another project unto itself.
If you are going apply non-Imail, external load balancing to Imail
then you can't slice a box any smaller than the above group of functions.
However, to offload the chores for receiving/sending mail to
Internet, I recommend dedicated SMTP gateways such as 2 or more
IMGate boxes, which themselves are failover due to SMTP MX redundancy
for incoming mail. Having such a larger user base and mail system,
you'll be a big, fat target for spammers. IMGate will handle that.
For the user database(s, I emphacie plural, again), I recommend an
external SQL RAID box since you will probably need access to the user
bases by other applications such as accounting.
That's the big picture as I see it for Imail6. For the fine strokes
and actually making it all work, well, hmmm, $$$$$. :))))
You will also need at least 2 DNS machines (again Imail server only
supports one so no failover) to support the IMGate machines for DNS
lookups to send mail. Imail won't be using DNS at all.
For list services for high volumes, I'd forget about Imail basic
lists and go with www.Listar.org on www.postfix.org on a FreeBSD or Linux box.
Good luck,
Len
http://BIND8NT.MEIway.com : Binary for ISC BIND 8.2.3 T9B for NT4 & W2K
http://IMGate.MEIway.com : Build free, hi-perf, anti-spam mail gateways
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