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In-Reply-To: <[EMAIL PROTECTED]>; from [EMAIL PROTECTED] on Sat,
Jun 16, 2001 at 03:42:05PM +0200
On Sat, Jun 16, 2001 at 03:42:05PM +0200, Nhan NGO DINH (OCIC Missionary Service)
wrote:
> I want to think about a cluster mail storage system, like an entry each 64k
> of mail, to avoid big message bodies in a db field. Anyway this should
> improve mailbox access speed and it could give mailbox availability for a
> cluster of servers. It seems to me a good idea, but too difficult to
> implement. May be there is already some stuff like that around here.
Hmmm. You want to improve mailbox speed by implementing a database,
spread across a cluster of servers, which efficiently handles records
varying in size from a few hundred bytes to many megabytes, in a
collection indexed on a single key, with multiple collections organized
for lookup by an ASCII string.
Sounds kind of like a hierarchical UNIX directory structure over NFS
to me! (NFS+maildir format)
Beyond that, I just don't see any benefit of storing the mail in a
database - are you ever going to try to do operations like "Look up the
3rd message in every user's mailbox" or "retrieve all messages with a
subject of 'Announcement' sent to every user whose name begins with
'z'"? Probably not, in which case a database will provide no benefit
and only degrade your performance. Unless of course you're doing it
for pure hack value (entertainment purposes) - in which case anything
goes.
If availability and scalability of performance is really critical to
you (e.g. supporting >25K users with > 99.99% uptime is a requirement)
consider implementing a cluster of servers accessing a shared mailspool
on a redundantly configured NFS server, running something like the
Cyrus mail system or another system which supports a maildir type
format, and using the POP server that comes with that,if qpopper isn't
enhanced to support maildir by then. I know this works because some
very large ISPs (Earthlink, PacBell) have used this general style of
architecture for their mail service; I've had some casual chats with
system designers at both of those.
-- Clifton
--
Clifton Royston -- LavaNet Systems Architect -- [EMAIL PROTECTED]
WWJD? "JWRTFM!" - Scott Dorsey (kludge) "JWG" - Eddie Aikau
