[syslog-ng] multiple file sources, worked - some have now gone silent

[Declan White]

I'm looking at a syslog-ng client that has multiple file() sources feeding a single destination unix-domain socket with flags(flow-control) and some disk-buffer.

Two days ago it was sending all these files and tracking their rotations fine etc. 
The destination server restarted, so the socket disappeared for a while, and the client ran out of the default buffering.
The intention is that it recovers when the destination returns and resumes reading the files where it left off.

When the server restarted data started flowing again.
But I've noticed it's no longer sending data from ALL of the file sources. Some have gone silent.

The log is saying nothing about the frozen sources. The statistics counters simply stopped incrementing for them.

This is kind of fatal. Has anyone seen this before or know how to avoid it? 

The faulty instance is still running, so if there's any way of interrogating it to find out its mental state, that's still possible.

syslog-ng 3.12.1
OS: Solaris

-- 
Declan White