Hello,
I am seriously considering using DBMail in our company for the
scalability and redundancy potential. We are currently using UW-IMAP
with mbx folders and our custom WebMail application.
I have the following questions and concerns that do not seem to be
covered by the documentation or a quick perusal of the past several
months of the list archives. I would appreciate any feedback that you
could give:
1. DBMail doesn't support "shared" mailboxes well -- where multiple
users can access the same mailbox. However I would assume it allows
multiple IMAP clients owned by the same user to access the same folder
at the same time. This isn't explicitly stated, and I just want to make
sure.
2. Like SquirrelMail, our WebMail uses the "SORT" IMAP feature to speed
mailbox access. This is VERY important for large mailboxes as it saves
reading ALL headers on every page view. I don't think most people would
want to throw out their existing IMAP server and replace it with
"dbmail" until you get SORT support. My users would be yelling about
the slowdown.
3. Once person on Google said that DBMail is not fully RFC compliant.
He gave the example of problems with message numbers as one example, see:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=40272cbb%241%40news.inveigle.net&rnum=40&prev=/groups%3Fq%3Ddbmail%26start%3D30%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26selm%3D40272cbb%25241%2540news.inveigle.net%26rnum%3D40
Have these problems been fixed, or are they non-issues?
4. With MySQL/InnoDB, I assume that the database size is really only
limited by the file system size. If we were to setup a SCSI RAID 5
array for the MySQL server, are there any considerations that would
seriously affect performance once we start getting 40Gb to 80Gb+ of
email data in one server?
5. It doesn't look like the programs such as "dbmail-smtp" have a
command line parameter that allow you to specify which "dbmail.conf"
file to use. This would be VERY helpful, for example, on an inbound
email server that may be filtering email for delivery on more than one
dbmail database.
6. How stable is the 2.0 branch and is there any significant reason to
use it over the 1.X branch? Is there a change list somewhere? Will
the upgrade from 1.X to 2.0 be seamless? When is 2.X expected to be
released?
7. With all the separate IMAP and POP daemons that run on the dbmail
server, each one presumably has its own database handle. Once you start
getting a lot of users using a cluster of IMAP/POP servers, you get a
high number of MySQL collections. What are the practical limits that
have been seen in terms of the maximum number of connections? Any
case-histories that can be used for comparison and specification design?
8. Has the "dbmail-smtp" branch been code reviewed by 3rd parties? I am
concerned about the possibility of SQL Injection.
Thank you.
-Erik Kangas
PS: Another interesting thing that could also be done in the future is:
* A separate database for user authentication. This way, you could have
multiple separate databases for email storage and the user
authentication could tell you which database to use for which user.
Moving users from one machine to another would then be seamless as the
front-end machine would be the same, only the database entries would
change. This becomes a concern once your big database server runs out
of room.
--
Erik Kangas, Ph.D. --- President of Lux Scientiae, Incorporated
Lux Scientiae: 1-800-441-6612 46 Central Street
FAX: 1-413-332-0598 Somerville, Massachusetts
Cell: 1-617-596-9558 02143, United States of America
AIM/ICQ/Yahoo Chat: Screen Name "luxsci"
[EMAIL PROTECTED] --- http://luxsci.com
