If postfix complained about can't access/delete/move a file, a likely culprit is filesystem damage, which can cause a while raft of problems with seemingly unrelated error messages. Other suspects are flaky hardware, bad RAM, or whatever else can cause the OS to lie to postfix about file access. These same things can mess up dovecot access too.
Unmount the drive and fsck it a few times. Power cycle / reboot the system. -- Noel Jones On 11/16/2018 10:05 AM, StarionTech (IMAP) wrote: > Yes, I thought all of those things too. Spent a good part of yesterday > eliminating them as the cause. > > top and iotop do not show any issues. No spam filtering on this box (it’s a > separate server/software). Drive is 1/3 full. No smart errors. > > The queue problem (and I don’t know why this isn’t handled better) turned out > to be a couple of corrupted messages in the queue. > > Had about 400 messages in the postfix queue, as soon as I deleted the two > corrupt messages, all 400 went out in almost 30 seconds. I found those two > messages from log entries, something about qmgr couldn’t delete or move the > message, permission denied. The messages had no attachments and looked to be > typical mail message traffic. I didn’t open them up though to see what was > wrong. > > The postfix queue problem is fixed, but message retrieval is still extremely > slow, so I’m still thinking there’s a dovecot issue. No error messages from > dovecot or postfix that I can see. > > I thought I read something about storing mail in maildir vs. some other > format, or even something about authentication errors causing slow dovecot > transactions. > > Jeff J. > > >> On Nov 15, 2018, at 4:35 PM, Håkon Alstadheim <ha...@alstadheim.priv.no> >> wrote: >> >> >> Den 15.11.2018 21:00, skrev StarionTech (IMAP): >>> Been moving along just fine for a couple years now, then in the last two >>> days, email has slowed to a crawl. >>> >>> Retrieving email via IMAP is very slow, progress bar in the mail client >>> shows that it is downloading messages almost constantly, like it never >>> closes the connection, or it’s getting the messages very slowly. The >>> server that dovecot/postfix is on has also bogged down to a crawl. >>> >>> The postfix queue is sitting with hundreds of queued up good customer email. >>> >>> It’s almost acting like dovecot is not getting the messages from postfix, >>> or they’re being delayed for some reason. >>> >>> How to approach fixing this? >> Check server logs for errors. Both dovecot and postfix struggling suggest >> some common underlying cause. >> >> Do measurements on Cpu, disk, cpu-wait. Which process is hogging the server >> ? Spam-ass acting up? Drives filling up? >> >> Gut instinct says one or more of your drives are failing, or you have file >> or file-system corruption, so if you are not running smartd, first priority >> is installing smartd/smartmontools and see what falls out. >> >>
