Scott Silva wrote:
on 1-9-2009 10:16 AM Stewart Dean spake the following:
1) Watching the syslog maillog has been intriguing...different IMAP
client show widely differently use patterns.
a) Users running TBird and Seamonkey have 2-5 imap sessions (ps -aef |
grep <userid>) *but* very little syslog activity...sparse occasional
logins and disconnects
b) Users running Exchange have only 1 imap sessions *but* every 5
minutes will generate login and disconnect messages (in and out in the
space of a second) for each folders. So for a user with 22 folders,
there will be 44 syslog messages in the maillog every 5 minutes.
Just curious....any thought as to which is more efficient and by how much?
2) When I try to switch a MacMail client over, it sees the new mail, but
not the old mail in the INBOX. How do I force re-indexing on the test
server?
By Exchange to you mean Outlook?
Outlook's (and Outlook Express) have poorly written IMAP implementations IMHO.
Outlook is first and foremost a client for an Exchange server, with somewhat
decent POP3 support. OE is just the POP3 and buggy IMAP.
Later versions added HTML support mainly to access hotmail.
They both seem to poll each folder for info instead of using IMAP calls.
First with question #2, it isn't clear to me if you need to have the
INDEX cache or dovecot-uidlist file rebuilt. Try removing one or the
other with a test account and see what happens (start with INDEX first).
If it is one or the other, the simplest thing might be to change the
location of these files in your configuration file for the new server.
Of course this will impact all of the clients (forcing them to rebuild
their indexes). For your sake, I hope it is just the INDEX files.
Here is what I know (or at least think I know), on some various E-mail
clients that should help to explain what you are seeing in the log
files. It can useful it getting your customers to have the appropriate
configuration for their client.
Thunderbird/Seamonkey use IMAP IDLE when possible and often use one
connection per monitored folder.
Depending on the version and configuration for Outlook/Outlook
Express/Entourage, you often get a periodic full synchronization polling
where the client checks the header of each message in the folder against
its internal index. This is even if it supports IDLE and is using IDLE
on the INBOX. I have seen older versions of Outlook Express open an IMAP
connection for every folder (subscribed or not) when simultaneously when
syncing (i.e. 10 folders, 10 connections).
More recent versions of MacMail likes to keep a full copy of every
messages including attachments in all subscribed folders. This is so it
can use spotlight.
A blackberry uses IDLE but, if you use more than one client at the same
time, RIM suggests that you may wish to have the administrator turn off
IDLE or have your blackberry to use POP. I am not kidding on this one.
We have a blackberry user where we found this change necessary.
Mutt and pine are mostly behave, but it is worth changing their default
settings in order to tune down the poll interval. rmail over stunnel has
more problems with postfix than it does with dovecot.
So I recommend to our users that they check for new mail no more
frequently than once every five minutes (once every ten minutes for
MacMail). My excuse is that they don't want to stomp on their
synchronization(s). They seem to buy this explanation. I check the log
files every so often and give users who check for new mail every minute
or less a stern finger wagging.
Hope this helps.
---Jack
