[Dovecot] DC testing observation and a question
I have been running a test DC IMAP server to evaluate the new release before migrating from 1.0.15 to 1.1.8. The test server access all the INBOX and homedir folder filesystems through NFS imports. The index file filesystem is local on both the production server and the test one.. This is messy in that when I ask some one tests using the test sever, the index has to be created or re-gennned, since the local index either doesn't exist or is several months old (from the last time a prospective upgrade was tested) and thus doesn't reflect data on the production DC IMAP server.
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?
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?
==== Once upon a time, the Internet was a friendly, neighbors-helping-neighbors small town, and no one locked their doors. Now it's like an apartment in Bed-Stuy: you need three heavy duty pick-proof locks, one of those braces that goes from the lock to the floor, and bars on the windows.... ==== Stewart Dean, Unix System Admin, Bard College, New York 12504 sdean@bard.edu voice: 845-758-7475, fax: 845-758-7035
on 1-9-2009 10:16 AM Stewart Dean spake the following:
I have been running a test DC IMAP server to evaluate the new release before migrating from 1.0.15 to 1.1.8. The test server access all the INBOX and homedir folder filesystems through NFS imports. The index file filesystem is local on both the production server and the test one.. This is messy in that when I ask some one tests using the test sever, the index has to be created or re-gennned, since the local index either doesn't exist or is several months old (from the last time a prospective upgrade was tested) and thus doesn't reflect data on the production DC IMAP server.
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?
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.
I think the open but inactive connections are less of a load on a server then the polling which would add to the I/O load, along with the syslog activity.
Just my opinion, though, and the usual disclaimers apply.
-- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!
Scott Silva wrote:
on 1-9-2009 10:16 AM Stewart Dean spake the following:
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?
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
participants (3)
-
Jack Stewart
-
Scott Silva
-
Stewart Dean