Thanks Sandy.  Pre-loading the domain related settings might actually make
sense for us.

What we are doing is moving to an external data source as we prepare to add
additional Imail machines to share the load, because our current server will
be maxed out very soon.  We prefer the idea load balancing multiple servers
instead of Imail's built in "peering" for large systems, because this has
the additional benefit of adding redundancy.

It sounds like you've probably set something like this up before, so if you
have any other recommendations I'm all ears.  We chose LDAP because it is
optimized for high-read/low-write queries...whereas SQL is the opposite.
We're using IBM's LDAP server.

So basically our setup will be X load balanced Imail servers which will
share the pop, imap, smtp connections.  The Imail servers will each have
their own spool folder, but will access the same LDAP userbase, and will
access the same directory structure for all the domains' mail folders.

We add several new domains per-day which is why we are looking into storing
the domain related information in LDAP also...to keep the machines in synch.
But pre-loading the data into registry at service startup might work out
alright.  We also have a SOAP interface we wrote for our billing/admin
software to talk to Imail so we can just use that to add new domains to each
Imail server on-the-fly as domains are added after the service has started.

I know there are huge benefits in using the registry database, but once a
system grows to multiple servers, I don't see that being feasible anymore.
Would you agree?

Bill



-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Sanford
Whiteman
Sent: Wednesday, January 01, 2003 1:52 PM
To: Bill B.
Subject: Re[2]: [IMail Forum] Problems changing external databases


> What  we  really  need  is  a function like 'SetDomain' where we can
> rewrite the storing of the information from the registry to LDAP.

As  someone who has written several custom userbase DLLs, including an
LDAP  interface,  I  can  assure you that you DO NOT want to store any
more  data  in  LDAP  than  is  actually  necessary.  LDAP  is  not  a
configuration  management  protocol  and  is  ill-suited  to the query
frequency  and  traffic  volume of a userbase-only implementation--let
alone trying to add hostbase information to the mix. If performance is
of  any  importance  at  all, you will find yourself wanting to reduce
and/or short-circuit your LDAP queries, not add *more* overhead.

You  are correct, of course, that IMail uses Registry hostbase data as
the  "anchor"  for userbase DLLs, regardless of where userbase data is
stored.  While  flexibility  there  might be nice, the design is quite
sensible,  given  the  read-mostly  nature  of  hostbase  data and the
tremendous read volume on that data.

The only practical way to create an LDAP "master" for hostbase data is
to  overwrite  the  Registry  settings from LDAP just once, at service
start,  then do not touch that LDAP area again. Believe me, as you see
the performance issues we wrangle with constantly--the cause, I should
mention,  for  my  constant  reminders  that  the Registry database is
hundreds of times more efficient than most external interfaces--you'll
reconsider this part of your design.

-Sandy


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