If you’ve upgraded to Jessie on a server (or any other machine without X), you might have started noticing strange new messages in your logs that look like this:

Nov 4 06:33:21 mail rsyslogd0: action 'action 20' resumed (module 'builtin:ompipe') [try http://www.rsyslog.com/e/0 ]
Nov 4 06:33:21 mail rsyslogd-2359: action 'action 20' resumed (module 'builtin:ompipe') [try http://www.rsyslog.com/e/2359 ]

As discussed in this bug report, that shouldn’t really happen and you can get rid of it by disabling logging to xconsole in rsyslog. Find this section of /etc/syslog/rsyslog.conf and comment it:

#daemon.*;mail.*;\
# news.err;\
# *.=debug;*.=info;\
# *.=notice;*.=warn |/dev/xconsole

That should take care of it until this is fixed upstream.