[Nut-upsuser] Bogus "UPS not available" messages

[Arjen de Korte]

Charles Lepple wrote:

>> Regarding the timestamp, when data is stale it is unimportant how stale
>> it is, it should not be used anymore. Most of the relevant data is very
>> volatile (battery charge, mains state) and after expiration becomes
>> useless and should not be relied upon anymore.
> There's a slim possibility that the timestamp could be useful in the
> upsc output, especially with drivers that have to cope with buggy
> hardware that does not always respond in the same time interval.

The problem here is, that upsc talks to the server and not directly to
the driver. You'd only be able to see the last time the server last
heard from the driver. Which usually happens every MAXAGE / 3 seconds,
or when the data from the UPS changes (in which case the driver pushes
the updated information to the server). If nothing changes, the only
communication between driver and server will be PING and PONG.

But unless the driver has declared the data stale (which is different
for each driver, but will be logged to syslog), you have to assume the
data is fresh. We don't put timestamps on each parameter in the driver,
so we can't make these available in the server either. We might show the
lastheard value for each driver (it's fairly easy to do so), but I
really don't see the added value. The timeouts that are hitting us, are
between the UPS and driver, not between driver and server.

Best regards, Arjen