--On Thursday, October 02, 2003 6:28 PM -0400 Sam Varshavchik
<mrs...@courier-mta.com> wrote:
Jeff Tucker writes:
Hi,
I've just upgraded to Courier-IMAP 2.1.2 from a version from a year ago.
The upgrade went fine and the server works fine but I noticed that
outgoing bandwidth usage is way up on the server.
Define 'bandwidth': that would be bandwidth as in bandwidth of IMAP
collections to clients, or bandwidth as in 'NFS bandwidth'.
Bandwidth is definitely to the customers. NFS traffic is on a separate
subnet and is monitored separately.
The only major change of note is the addition of custom IMAP keywords.
The impact on IMAP clients should be minimal; it will results in a little
bit of new traffic, but not that much.
Custom IMAP keywords do generate additional filesystem I/O. So the only
thing that I can think of is that most of your IMAP clients can use
custom keywords, if available on the server, and suddenly they see that
they can, and go hog-wild.
That doesn't sound like the case. Hmm, I've just thought of a possible
answer based on some emails I've gotten. A couple people have emailed me
reporting duplicate emails, i.e. they're downloading emails they've seen
before. Has the POP system changed so that if a message was marked as seen
using a year-old Courier installation and I bring up the new one, everyone
will download every message once more, assuming they had been using "leave
on server"? If that's the case, then some users with 20,000 messages in
their Inboxes could all start pulling all of those messages again,
resulting in the high bandwidth usage. If this scenario is correct, then
once everyone had downloaded another copy of every message, the bandwidth
would drop to normal.
I have noticed a new file in some of the user's Maildirs:
courierpop3dsizelist. The old server didn't use that file.
If my theory is correct, is there any way to stop this from happening? I'm
going to get a lot of complaints if lots of people start downloading old
messages.
Jeff