=?UTF-8?B?TWFydMOtbiBNYXJxdcOpcw==?= <martin@2ndquadrant.com> writes:
> 2014-05-16 11:56 GMT-03:00 Graeme Gemmill <graeme@gemmill.name>:
>> $ ./pg_ctl start -D /mnt/post/pgsql/data &
>> [1] 3692
>> [postgres@localhost bin]$ pg_ctl: could not open PID file
>> "/mnt/post/pgsql/data/postmaster.pid": Protocol error
> Looks like a libpq - backend server mismatch.
No --- pg_ctl is trying to read the postmaster's PID file, and it's
getting some bizarre error from fopen(). I have no idea exactly what
"Protocol error" might mean in this context. It would make some sense
if the data directory were on NFS or other network-based file system,
but otherwise it's kind of weird.
Anyway this is a filesystem problem. libpq is not involved. I would
venture that it's either a kernel bug or some misconfiguration of the
virtual environment. The fix is below Postgres' level, for sure.
regards, tom lane
