Thanks a lot to everybody
First step I will upgrade to dovecot2.
I will write my experiences.
"Running with fsync disabled is like having sex with a Bangkok prostitute without a condom while juggling chainsaws while driving drunk at 250kph at night without headlights."
:-)
Gabor
2012-10-27 20:27 időpontban Stan Hoeppner ezt írta:
On 10/27/2012 6:58 AM, Bernics Gábor | Penta Unió Zrt. wrote:
I
use dovecot LDA (+sieve) with maildir. conf: http://pastebin.com/9fhYD58g [1]
Next time simply paste "dovecot
-n" output into your email.
Assuming Dovecot is the only program
accessing the maildirs, try:
maildir_very_dirty_syncs=yes
That
may help some.
It may not have been a factor in this case, but note
doing a full text search on a large mailbox on
maildir you will see latency, and it is unavoidable. Neither a single 7.2K SATA spindle nor md/RAID1 pair of
service all the sector requests in a timely fashion.
Also, I noticed you disabled fsync. This is a very very bad idea for a mail server. If you lose power, or suffer a kernel/hardware/etc crash, you lose the Linux buffer cache contents. Thus, you may lose emails that haven't been flushed to disk, and
that when anyone is this hardware with them, has enough seek capacity to possibly get index file
corruption if mmap'd pages haven't been flushed.
Running with fsync disabled is like having sex with a Bangkok prostitute without a condom while juggling chainsaws while driving drunk at 250kph at night without headlights.
fsync does hurt write performance to a degree, especially with maildir storage, but will likely be invisible on a small server with few users/light load. And it will prevent potentially severe problems with file corruption and/or lost emails.