[Nut-upsdev] bestfortress driver establishes/loses/establishes communication and so on...

[Arnaud Quette]

Hi Stuart

2012/1/19 Stuart D. Gathman <stuart at bmsi.com>:
> Long ago, Nostradamus foresaw that on Jan 18, Arnaud Quette would write:
>
>> I really have to have a closer look there.
>> I'm suspecting some race condition between upstart, sysV compat layer,
>> udev and NUT starting, which could result in this.
>
>
> Yes, on Fedora 16, you have to start nut-server before nut-monitor, and
> systemd tries to start them at once.  Haven't got around to reporting that.
> I don't think this problem is fortress specific.

cc'ing Michal for this.
I know that this was more a preliminary support than something really complete.
quickly looking at the service files, nut-monitor is marked to be
started after nut-server, and nut-server after nut-driver
so you may be hitting a systemd bug.

>>> The problem is that soon after nut started successfully, communication to
>>> the UPS is lost, with "data stale". After some minutes, communication
>>> gets
>>> re-established. Then lost again and so on and on and on...
>
>
> This has been a long standing problem with the fortress driver.  The
> UPS often corrupts the status output (hence the checksum).  The driver
> correctly discards the bad checksums, but Nut gets all antsy about missed
> statuses.  I generally adjust upsmon.conf to compensate.  If I'm not the
> only fortress user left, I'll have to see if I can tweak the driver.
> Perhaps it should leave status unchanged after a single corrupt
> record from the UPS instead of reporting a problem.

if only the checksum is corrupted from time to time, and not the data,
it may be worth to indeed not declare directly staleness.
I've just committed a patch to trunk (r3400) to get more visibility on
the received data, and impact on ignoring checksum.

cheers,
Arnaud
-- 
Linux / Unix Expert R&D - Eaton - http://powerquality.eaton.com
Network UPS Tools (NUT) Project Leader - http://www.networkupstools.org/
Debian Developer - http://www.debian.org
Free Software Developer - http://arnaud.quette.free.fr/