Error: nfs_flush_file_handle_cache_dir: rmdir(/var/mail) failed: Device busy
Dovecot tries to flush NFS cache by doing this rmdir(). It is intended to fail, but not with EBUSY. I guess /var/mail is your NFS mount root? That's why this is failing. There's really no good way to solve this.
Hmm....sorry, I should have mentioned - /var/mail is actually local - only the /home bits are NFS mounted. Is that even more concerning?!
/var/mail is still a mount point I think?
It is indeed!
Anyway, if your INBOXes are on local server, I guess there's only a single server accessing users' mails then? If that's the case, just set mail_nfs_*=no and be happy.
I think this is where our some what complicated system is an issue - mail that goes into /var/mail is only because the user's home directory is over quota and so the mail cannot be delivered into ~/Mail/inbox. We used to have a script that would go round daily and rescue /var/mail bits (when we also used UW-IMAP), but the mbox_snarf plugin is a nice way to do this in a more user-friendly manner. No users are reporting any issues here, even those referenced with the nfs_flush_file_handle_cache_dir errors, so we'll ignore that one for now.
BTW, and I'm sure you know and have heard this before - but the difference in the demands on the hardware between Dovecot with its indexes and UW-IMAP accessing some huge mboxes is huge - insanely so. All the theory in my head from reading about Dovecot said it should be, but nice to see that played out in reality. Quote of the day: "my inbox is quicker than its ever been". :-)
Thanks for your time ~~ Ade
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