Aki Tuomi <aki.tuomi@dovecot.fi> writes:
Yes. You deffo are looking at several reasons for slowness.
I can only recommend moving into maildir or sdbox format, and probably new HDD too.
https://wiki2.dovecot.org/Tools/Doveadm/Sync here is example of 'converting' between mailbox formats using dsync. You should also read https://wiki2.dovecot.org/Migration/MailFormat
mbox format has been known to act up with dsync occasionally, so I recommend using
doveadm backup maildir:~/Maildir
Thanks, I've done that now, and things are looking much better.
I rediscovered that I've configured postfix to deliver locally using dovecot-lmtp - which meant that I then only needed to change dovecot's mail_location setting, and nothing at all in the postfix config.
Many thanks! - Neil