[Dovecot] strange email client problems
I've got some issues with dovecot, that I need to resolve, I only have
about 20 users in the office, but the average disk space used by each
user is anywhere from 1GB up to at the extreme end of the scale 7GB.
I'm using the mailbox format. The server is a P4 2.8 with a 1GB of ram
and run off 250GB SATA disks. most users have lots of structured
folders going as deep as 6 levels. The problems I'm getting are odd
the problems that I'm getting at the moment are
"cannot copy mail to sent folder", but sends the message fine, this doesn't happen all the time but happens to everyone but me... I'm using OS X's Mail.app which seems to always work:) all my users are using W2K and either ThunderBird or Mozilla
The other problem which I've been made aware of...
The users get the "loading message" or "opening messages" and the egg timer goes round but never completes. I managed to clear the problem by getting the user to close their email client and then kill their IMAP processes on the server, when the user logs in again the client responds correctly.
Is there something I'm doing wrong with the configuration of dovecot? would using MailDir help, I dont want to migrate from Mailbox unless this change will make things better, I understand their are benefits from using MailDir, but I dont know if I will continue to see the same problems if I migrate.
Any help or advise would be great, I should add that everyone is connecting to the server over SSL
Gabe
On 17.3.2005, at 19:18, Gabriel Granger wrote:
The users get the "loading message" or "opening messages" and the egg timer goes round but never completes. I managed to clear the problem by getting the user to close their email client and then kill their IMAP processes on the server, when the user logs in again the client responds correctly.
You mean just closing the email client didn't kill the imap process on server? Was it using any CPU?
Is there something I'm doing wrong with the configuration of dovecot? would using MailDir help, I dont want to migrate from Mailbox unless this change will make things better, I understand their are benefits from using MailDir, but I dont know if I will continue to see the same problems if I migrate.
How large are your largest mailboxes? Maildir probably won't help anyway with these problems.
Any help or advise would be great, I should add that everyone is connecting to the server over SSL
But you didn't say what Dovecot version you were using. Most importantly, 0.99.x or 1.0-stable/test?
Hi Timo,
Thanks for your reply,
Closing the email client doesn't kill the process, it does sometimes but normally have to wait a while (5mins or more). When you refer to CPU load are you talking about on the server itself? if so I don't believe it is. I will check next time this happens.
My largest users mailbox file is 200Mb with the total disk space used
by all their mail folders is 6GB. Is there any information regarding
limits on what is a safe maximum size for a mailbox folder? I try to
get my users to keep their inboxes under 200 messages or 50Mb.
Currently I'm gettting my heavy users to reduce their inboxes from
150Mb down to something sensible.
As for the the version of Dovecot I'm running its 1.0-stable on linux(SuSE 9.1, tho I wish it was a debian box) a 1U Intel P4 2.4 1GB DDR 2 * SATA 250 Drives running RAID 1.
Regards
Gabe
On 18 Mar 2005, at 18:19, Timo Sirainen wrote:
On 17.3.2005, at 19:18, Gabriel Granger wrote:
The users get the "loading message" or "opening messages" and the egg timer goes round but never completes. I managed to clear the problem by getting the user to close their email client and then kill their IMAP processes on the server, when the user logs in again the client responds correctly.
You mean just closing the email client didn't kill the imap process on server? Was it using any CPU?
Is there something I'm doing wrong with the configuration of dovecot? would using MailDir help, I dont want to migrate from Mailbox unless this change will make things better, I understand their are benefits from using MailDir, but I dont know if I will continue to see the same problems if I migrate.
How large are your largest mailboxes? Maildir probably won't help anyway with these problems.
Any help or advise would be great, I should add that everyone is connecting to the server over SSL
But you didn't say what Dovecot version you were using. Most importantly, 0.99.x or 1.0-stable/test?
On 21.3.2005, at 13:32, Gabriel Granger wrote:
Closing the email client doesn't kill the process, it does sometimes but normally have to wait a while (5mins or more). When you refer to CPU load are you talking about on the server itself? if so I don't believe it is. I will check next time this happens.
Or the load in general? That sounds like Dovecot is busy re-reading the mbox file.
My largest users mailbox file is 200Mb with the total disk space used by all their mail folders is 6GB. Is there any information regarding limits on what is a safe maximum size for a mailbox folder? I try to get my users to keep their inboxes under 200 messages or 50Mb.
Currently I'm gettting my heavy users to reduce their inboxes from 150Mb down to something sensible. ..The users get the "loading message" or "opening messages" and the egg timer goes round but never completes. I managed to clear the problem by getting the user to close their email client and then kill their IMAP processes on the server, when the user logs in again the client responds correctly.
OK, sounds like a new message has arrived to mbox and Dovecot re-reads the whole mbox which takes a while. Although Dovecot 1.0-stable doesn't anymore re-read the mbox as long as it's selected.. Maybe the clients open another connection to server which.. Try setting:
mbox_very_dirty_syncs = yes
I will set that option tonight and see how what happens when my users login tomorrow morning. With regards to the load of the server its about 0.03 at present and when a user complained about "Loading messages" about 30mins ago, I checked the server and it was abut the same. I'm really not sure how to see the load of the HD's from the console or even what I could compare it against.
Mem: 1035180k total, 1014672k used, 20508k free, 33556k buffers Swap: 1052216k total, 0k used, 1052216k free, 920644k cached
I notice the server is using a lot of real memory but with loads of swap available for use if thats of any use. When I used to use UW-IMAP i used to get a lot more CPU load which has since disappear now that I'm using Dovecot. I take it that setting
mbox_very_dirty_syncs = yes
will cause delays with users that have large mailboxes?
Regards
Gabe Granger
On 21 Mar 2005, at 12:42, Timo Sirainen wrote:
On 21.3.2005, at 13:32, Gabriel Granger wrote:
Closing the email client doesn't kill the process, it does sometimes but normally have to wait a while (5mins or more). When you refer to CPU load are you talking about on the server itself? if so I don't believe it is. I will check next time this happens.
Or the load in general? That sounds like Dovecot is busy re-reading the mbox file.
My largest users mailbox file is 200Mb with the total disk space used by all their mail folders is 6GB. Is there any information regarding limits on what is a safe maximum size for a mailbox folder? I try to get my users to keep their inboxes under 200 messages or 50Mb. Currently I'm gettting my heavy users to reduce their inboxes from 150Mb down to something sensible. ..
The users get the "loading message" or "opening messages" and the egg timer goes round but never completes. I managed to clear the problem by getting the user to close their email client and then kill their IMAP processes on the server, when the user logs in again the client responds correctly.
OK, sounds like a new message has arrived to mbox and Dovecot re-reads the whole mbox which takes a while. Although Dovecot 1.0-stable doesn't anymore re-read the mbox as long as it's selected.. Maybe the clients open another connection to server which.. Try setting:
mbox_very_dirty_syncs = yes
(05.03.21 kl.15:03) Gabriel Granger skrev följande till Timo Sirainen:
I will set that option tonight and see how what happens when my users login tomorrow morning. With regards to the load of the server its about 0.03 at present and when a user complained about "Loading messages" about 30mins ago, I checked the server and it was abut the same. I'm really not sure how to see the load of the HD's from the console or even what I could compare it against.
Mem: 1035180k total, 1014672k used, 20508k free, 33556k buffers Swap: 1052216k total, 0k used, 1052216k free, 920644k cached
I notice the server is using a lot of real memory but with loads of swap available for use if thats of any use. When I used to use UW-IMAP i used to get a lot more CPU load which has since disappear now that I'm using Dovecot.
The use of real memory is no good indicator since the OS will use as much as possible for buffers. If the system starts using swap in a big way then this is a good indication that you are running out of memory or I/O.
To see a general system load (in Linux) use vmstat. root# vmstat 5 10|cut -c 8- ----------memory---------- ---swap-- -----io---- --system-- ----cpu---- swpd free buff cache si so bi bo in cs us sy id wa 12 57104 50004 1813592 0 0 1 0 1 1 3 1 93 4 12 16288 50064 1855692 0 0 8429 536 1439 1252 3 1 88 8 12 39288 50100 1833692 0 0 5026 973 1375 1048 4 2 88 7 12 13332 49700 1858300 0 0 17262 905 1762 889 17 2 71 10 12 90096 49860 1781368 0 0 35019 1434 1801 1791 13 3 60 24
Of special interest is si, so, bi, bo, wa. so: Amount of memory swapped to disk (/s). wa: Time spent waiting for IO. (There are other info to get via vmstat too. Use man :)
Cheers, Jens
'This mail automatically becomes portable when carried.' Jens Låås Email: jens.laas@data.slu.se
Department of Computer Services, SLU Phone: +46 18 67 35 15
Vindbrovägen 1
P.O. Box 7079
S-750 07 Uppsala
SWEDEN
participants (3)
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Gabriel Granger
-
Jens Laas
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Timo Sirainen