Hi,

I'm running some Dovecot servers configured with LVS + Director + Backend + NFS and version 2.2.36.3 (a7d78f5a2).

In the last days I see an increased number of these error:

Error: o_stream_send_istream(/nfs/mail/company.com/info/Maildir/.Sent/tmp/1562771349.M255624P9151.pop01) failed: Broken pipe

always with action "Disconnected in APPEND", when users try to upload a message in Sent or Drafts.

Here the logs:

Director:
Jul 10 14:53:06 imap-login: Info: proxy(info@company.com): started proxying to 10.0.0.20:143: user=<info@company.com>, method=PLAIN, rip=84.1.2.3, lip=195.1.2.3, lport=993, TLS, session=<eA6XKFONwP1f5Sh4>
Jul 10 15:09:56 imap-login: Info: proxy(info@company.com): disconnecting 84.1.2.3 (Disconnected by client: EOF(0s idle, in=648413, out=6602)): user=<info@company.com>, method=PLAIN, rip=84.1.2.3, lip=195.1.2.3, lport=993, TLS, session=<eA6XKFONwP1f5Sh4>

Backend:
Jul 10 14:53:06 pop01 dovecot: imap-login: ID sent: x-session-id=eA6XKFONwP1f5Sh4, x-originating-ip=84.1.2.3, x-originating-port=64960, x-connected-ip=195.1.2.3, x-connected-port=993, x-proxy-ttl=4: user=<>, rip=84.1.2.3, lip=195.1.2.3, secured, session=<eA6XKFONwP1f5Sh4>
Jul 10 14:53:06 pop01 dovecot: imap-login: Login: user=<info@company.com>, method=PLAIN, rip=84.1.2.3, lip=195.1.2.3, mpid=9151, secured, session=<eA6XKFONwP1f5Sh4>
Jul 10 14:53:07 pop01 dovecot: imap(info@company.com) session=<eA6XKFONwP1f5Sh4>: ID sent: name=Thunderbird, version=60.7.2
Jul 10 15:09:56 pop01 dovecot: imap(info@company.com) session=<eA6XKFONwP1f5Sh4>: Error: o_stream_send_istream(/nfs/mail/company.com/info/Maildir/.Sent/tmp/1562771349.M255624P9151.pop01) failed: Broken pipe
Jul 10 15:09:57 pop01 dovecot: imap(info@company.com) session=<eA6XKFONwP1f5Sh4>: Disconnected in APPEND (1 msgs, 48 secs, 0/2657336 bytes) in=886661 out=26654 del=1 expu=0 trash=0

I can't understand if is a network problem (Firewall? Load Balancer? Switch?) or a users LAN problem. Or others.

When this happen user see an error message like "Unable to save email in Sent folder".

Any suggestions?

Thanks

-- 
Alessio Cecchi
Postmaster @ http://www.qboxmail.it
https://www.linkedin.com/in/alessice