dovecot - Aug 2009 - IMAP activity after disconnect

Howdy,

I'm running Dovecot 1.1.16 on a staging server to do some testing before 
building a new server and moving a bunch of qmail/vpopmail/courier 
accounts over.

I wanted to test the migration of courier accounts to dovecot with a few 
clients, so I copied over a few large accounts.  All went well with a 
small account (100+ messages) when accessing the account via POP - no 
re-downloads after adjusting the uidl format.  IMAP looks good as well 
after running the conversion script and setting the namespace properly.

However, one thing I copied over without paying much attention was a 
non-quota'd spam box that has literally not been checked in at least a 
year:

[root at nac /var/vmail/xxx.com/spork/Maildir/.Spam]# ls new/| wc 
-l
    70501

Mail.app valiantly tried to sync this, but when I realized just how huge 
this was, I took the account offline and quit the app.  However it seems 
like Dovecot is still busy doing something in that mailbox:

lsof: no pwd entry for UID 5000
imap    27515     5000    7uW   VREG       0,95     3372  2968764 
/jails/nac.xxx.com/var/vmail/xxx.com/spork/Maildir/.Spam/dovecot.index.log
lsof: no pwd entry for UID 5000
imap    27515     5000    8u    VREG       0,95      488  3007349 
/jails/nac.xxx.com/var/vmail/xxx.com/spork/Maildir/.Spam/dovecot.index
lsof: no pwd entry for UID 5000
imap    27515     5000    9u    VREG       0,95    25195 27064933 
/jails/nac.xxx.com/var/vmail/xxx.com/spork/Maildir/.Spam/dovecot-uidlist
lsof: no pwd entry for UID 5000
imap    27515     5000   10r    VDIR       0,95 15171072  2968758 
/jails/nac.xxx.com/var/vmail/xxx.com/spork/Maildir/.Spam/new

My guess is it's trying to build an index.  This process is chewing up 
100% of whatever cpu it lands on.  Is this expected behavior (not the huge 
cpu usage, but the imap server continuing to work on the box after the 
client has logged out)?

Are there any config settings I've missed to sort of put a cap on how much 
cpu/time dovecot will spend on a task like this?  So far this has been 
running for about 20 minutes.  I'm going to kill it and manually delete 
the spam since I'm not familiar enough with gdb to dig in and see just 
what it's doing (although my guess is indexing).

On the upside, I have some serious spam magnet addresses in this test 
domain, so now I've got a great platform to test my amavis/postfix/policy 
skills. :)

Thanks,

Charles

___
Charles Sprickman
NetEng/SysAdmin
Bway.net - New York's Best Internet - www.bway.net
spork at bway.net - 212.655.9344

On Sat, 2009-08-29 at 01:57 -0400, Charles Sprickman
wrote:
> [root at nac /var/vmail/xxx.com/spork/Maildir/.Spam]# ls new/| wc 
> -l
>     70501
> 
> Mail.app valiantly tried to sync this, but when I realized just how huge 
> this was, I took the account offline and quit the app.  However it seems 
> like Dovecot is still busy doing something in that mailbox:
It's most likely busy moving all the messages from new/ to cur/. You
could have checked that with strace.
> My guess is it's trying to build an index.  This process is chewing up 
> 100% of whatever cpu it lands on.  Is this expected behavior (not the huge 
> cpu usage, but the imap server continuing to work on the box after the 
> client has logged out)?
Yes. These kind of long-running tasks are very rare, so I haven't
bothered adding any "is client still there?" checks to the code.
> Are there any config settings I've missed to sort of put a cap on how
much
> cpu/time dovecot will spend on a task like this?
Nope.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part
URL:
<http://dovecot.org/pipermail/dovecot/attachments/20090906/8a1037cd/attachment-0002.bin>