So it turns out can't set DEADTIME with snmp-ups. It isn't listed as a 
supported optional setting on the man page. If you try to set it the connection 
doesn't work. I'm not sure what this means in regards to setting pollfreq to a 
higher value like say 60.

From: Nut-upsuser 
[mailto:nut-upsuser-bounces+jgould=cddiagnostics....@lists.alioth.debian.org] 
On Behalf Of Jason Gould
Sent: Tuesday, March 31, 2015 9:08 AM
To: Charles Lepple
Cc: NUT Users
Subject: Re: [Nut-upsuser] Tripplite SNMPwebcard communication lost and 
established randomly

I missed that snmp-ups set pollfreq to 30 by default. I'd hope that it would 
set deadtime to an appropriate value as well than, no? Is there a way to query 
what the settings are or what the defaults are?

I'm going to set POLLFREQ=30 and DEADTIME = 90 and see if that has any effect. 
I'll check for the logs. And if that doesn't get my anywhere I'll look at 
trying to simulate with snmpwalk like you mentioned.

Thanks.

From: Charles Lepple [mailto:[email protected]]
Sent: Monday, March 30, 2015 11:20 PM
To: Jason Gould
Cc: NUT Users
Subject: Re: [Nut-upsuser] Tripplite SNMPwebcard communication lost and 
established randomly

[please use Reply-All to keep the list CC'd, thanks]

On Mar 30, 2015, at 11:04 PM, Jason Gould 
<[email protected]<mailto:[email protected]>> wrote:


Thanks.  I should also mention the freenas server is setup with an lacp lagg.

I will also mention that even when not setting pollfreq (leave as default) the 
issue still occurs.
It looks like the default for pollfreq is actually 30 on snmp-ups, which means 
you would want DEADTIME to be at least 2x that in order for a single stale data 
event to not trigger the COMMBAD message, and the default is only 15. As you 
can imagine, choosing default values that work across all the UPS models is 
somewhat tricky.

FreeNAS has an additional parameters area to add to the upsmon.conf. I verified 
it does actually write to the config file.
Good to know.

The messages I posted are just what pops up in a putty session. Is there any 
debugging or logs I can look at to get a better idea of what happens when this 
is occurring?
NUT drivers write to syslog - you might need to check with the FreeNAS folks to 
see what happens to those messages. On a regular BSD box, it might be 
/var/log/messages

As for snmpwalk, is there a command I can let run to determine if there is a 
problem? Because that is the problem, it happens randomly so unless I sit in 
front of a computer for 12 hours ready to do something at just the right time, 
I won't catch it.
I'd run it in a loop (maybe with a 'sleep 30' to mimic the polling interval of 
NUT), and check the log file every so often. snmpwalk should have more 
descriptive error messages than snmp-ups, but they both use the same underlying 
library, so YMMV. There are a few flags that you can add to snmpwalk to adjust 
the error output.

I also looked at the Cisco router and it isn't showing any packet loss.
It is possible that packet loss is happening on the SNMPwebcard. Those sorts of 
cards typically do not have fast CPUs. But the snmpwalk results should shed 
some more light on this.

On Mar 30, 2015 8:30 PM, Charles Lepple 
<[email protected]<mailto:[email protected]>> wrote:
On Mar 30, 2015, at 10:41 AM, Jason Gould 
<[email protected]<mailto:[email protected]>> wrote:

Just started using NUT and having a problem. I'm not sure if it is even NUT 
that is causing the issue.
I'm running the latest FreeNAS 9.3 release.
Network UPS Tools upsmon 2.7.2.
The UPS is a Tripplite SU6000RT4UHVPM with the SNMPwebcard installed.
I'm trying to use the SNMPwebcard, not USB or Serial. I've updated the 
SNMPwebcard to the latest firmware version (see below).

Thanks, this is good background information.

In FreeNAS I was able to create a connection to the UPS by simply adding the IP 
address for the Port and defining the driver as "Various ups 3 (various) SNMP - 
RFC 1628 (snmp-ups)". After that querying it just worked via "upsc tripplite". 
And everything looks fine. However after a few hours I started getting emails 
and messages in the console about communication lost (COMMBAD) and shortly 
after it being established. This happens over and over again. I thought perhaps 
I needed to change some of the settings in ups.conf. I tried adjusting the 
pollfreq up to 30, using an snmp_version v2c, and a few other adjustments. 
However the behavior persists.

There are two stages here: the snmp-ups driver polls every 'pollfreq' seconds, 
and upsmon sends a warning if an UPS is stale for longer than DEADTIME seconds 
(as set in upsmon.conf). So if you increase pollfreq, you would probably want 
to increase DEADTIME as well. (I'm not sure how FreeNAS exposes this setting.) 
The upsmon.conf documentation recommends multiplying pollfreq by three to get 
DEADTIME. You may want to go higher than that, depending on how long the 
interval is between COMMBAD and COMMOK (the messages you quoted only have 
one-minute resolution).

Unfortunately, it looks like snmp-ups goes into COMMBAD mode if even one of the 
SNMP queries fails (and it queries a lot of OIDs), so you would need to rely on 
DEADTIME to filter out any transient packet loss. You might also see if your 
firewall or switch can prioritize SNMP packets using QoS settings - I am not 
familiar with how many times NetSNMP retries, but SNMP is UDP-based.

You could also try running 'snmpwalk' by hand against the SNMPwebcard to see if 
it experiences the same packet loss. If that doesn't work, I think you have a 
case for Tripp Lite support.

--
Charles Lepple
clepple@gmail




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