[Dovecot] Delay email!
I am using postfix + dovecot 2.0.6 + mailman
And others 2 serves with only postfix and dovecot writing at same storage with OCFS2.
We are having problens with IOwait, and still trying to figure out why that is happen!
But, problem becomes much worse when some emails are used in mailman, when it happens all 3 serves became really slow. iowait goes to 80.
Does anyone have an idea how to slow down the dovecot lda ?
I want it to nit to iwrite so much email, at least take a small break between each mail!!
Any ideias?
Thanks!
[]'sf.rique
On Thu, 2010-12-09 at 17:15 -0200, Henrique Fernandes wrote:
I am using postfix + dovecot 2.0.6 + mailman
And others 2 serves with only postfix and dovecot writing at same storage with OCFS2.
We are having problens with IOwait, and still trying to figure out why that is happen!
sdbox/mdbox format should reduce disk IO compared to maildir.
But, problem becomes much worse when some emails are used in mailman, when it happens all 3 serves became really slow. iowait goes to 80.
Does anyone have an idea how to slow down the dovecot lda ?
By telling Postfix to limit the number of simultaneous dovecot-lda processes. In master.cf you have:
# service type private unpriv chroot wakeup maxproc command + args
So change the dovecot-lda entry's maxproc from "-" to however many simultaneous dovecot-ldas you want.
Yeap, already done this! hahahah
now is just 3 process. maxproc.
We are thinking is use sdbox but we have to be a lot of sure that will help a LOT other wise we gona be "stick" to dovecot for no big reason!
We just did a huge migration from mbox to maildix. Still some problems in some accounts but is ok!
Thanks!
Other time i saw some one using indexes in local disk. This should help ? i mean, we would have 2 index one in each server that have imap and pop, so each tim eindex would have to be written each time it logins on each server right ? this would not gain lot os performance right ?
[]'sf.rique
On Thu, Dec 9, 2010 at 9:20 PM, Timo Sirainen tss@iki.fi wrote:
I am using postfix + dovecot 2.0.6 + mailman
And others 2 serves with only postfix and dovecot writing at same storage with OCFS2.
We are having problens with IOwait, and still trying to figure out why
On Thu, 2010-12-09 at 17:15 -0200, Henrique Fernandes wrote: that
is happen!
sdbox/mdbox format should reduce disk IO compared to maildir.
But, problem becomes much worse when some emails are used in mailman, when it happens all 3 serves became really slow. iowait goes to 80.
Does anyone have an idea how to slow down the dovecot lda ?
By telling Postfix to limit the number of simultaneous dovecot-lda processes. In master.cf you have:
# service type private unpriv chroot wakeup maxproc command + args
So change the dovecot-lda entry's maxproc from "-" to however many simultaneous dovecot-ldas you want.
On 9.12.2010, at 23.31, Henrique Fernandes wrote:
We are thinking is use sdbox but we have to be a lot of sure that will help a LOT other wise we gona be "stick" to dovecot for no big reason!
You can always use dsync to migrate between different mailbox formats. You could also for example switch only some users to sdbox and keep others in Maildir to see if the performance improves.
Other time i saw some one using indexes in local disk. This should help ? i mean, we would have 2 index one in each server that have imap and pop, so each tim eindex would have to be written each time it logins on each server right ? this would not gain lot os performance right ?
Difficult to say.
We migh try index on local disc to see what happens.
We use dsyn to migrate between boxes, but as i said, some times dsync crashed, and as long as we are using sdbox, i don`t know any other tool that can migrate mails from that format to another! Maybe imapsync or some thing...
Still studing!
Gonna upgrade from ocfs2 1.4 to ocfs2 1.6 see if makes any improves.
[]'sf.rique
On Thu, Dec 9, 2010 at 10:42 PM, Timo Sirainen tss@iki.fi wrote:
On 9.12.2010, at 23.31, Henrique Fernandes wrote:
We are thinking is use sdbox but we have to be a lot of sure that will help a LOT other wise we gona be "stick" to dovecot for no big reason!
You can always use dsync to migrate between different mailbox formats. You could also for example switch only some users to sdbox and keep others in Maildir to see if the performance improves.
Other time i saw some one using indexes in local disk. This should help ? i mean, we would have 2 index one in each server that have imap and pop, so each tim eindex would have to be written each time it logins on each server right ? this would not gain lot os performance right ?
Difficult to say.
participants (2)
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Henrique Fernandes
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Timo Sirainen