At 10:37 AM 18/12/2002 +1100, John Heller wrote:
Does anybody have any benchmarks or even subjective opinions on how dbmail
performs when dealing with large volumes of mail?
Subjective opinion is that it works well. But there are at least four
definitions of large volumes:
1. mail traffic into site
2. client traffic viewing/retrieving mail
3. mail volume preserved on server
4. large IMAP folders
We have about 100-200MB/day incoming, up to several clients accessing mail
every second, and a low volume of preserved email (up to 5GB, usually
around 2GB).
We're running PostgreSQL and the server does not even show the load. But,
as noted elsewhere, it is important to make sure that PostgreSQL is
configured properly for such a large DB especially if you have high levels
of transient data.
We did have one inactive account with 86000 messages in INBOX, and that
took a few minutes to open with IMAP -- but I *think* that's an IMAP
problem since, even to retrieve the first twelve messages it insisted on
getting summaries for all of them.
If you choose to use MySQL, the only warning that may be relevant is that
it does not have great locking, so if you have a large volume of active
connections you may end up with contention problems (meaning slower
retrieval/updates etc).
I am considering transfering all of our user's mail, including all their
folders of saved and archived mail to dbmail. This will come to around
40-50GB, which makes for quite a large messageblks table. I don't have
enough experience with mysql to know how it will deal with that.
Neither do I. Assuming you put the effort into configuring postgresSQL
properly, it should have no problems.
Presumably the more mail that is in the system, the slower things will get.
Why? The only issues I have seen relate to IMAP mailbox sizes.
I can see that dbmail will require less dicipline from users and will cope
better with those who let their inbox grow to hundreds of megabytes, but
is it going to get slower and slower over time?
Sadly, this is probably also untrue -- but it may not be DBMail's fault. I
don't have much experience with IMAP, but what I have seen using Horde/IMP
suggests that it is not very good at handling large mailboxes.
One of the features that is often overlooked when codsidering DBMail is
that you get all the advantages of a *real* database
Hope this helps....
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