How to roll-back "Not supported" items

[rushowr]

Great News

I'm soooo glad to hear it!

Oh and yes, I did have a cron job running every 30 minutes to roll back those not supported items....

[zac]

How to see why an snmp item goes "unsupported"

I've got a temp probe in the server room that responds to snmp requests. I've got it in zabbix and several times a day any of the three OIDs go "unsupported". Now I know the beta3 product will address this by retrying, but I'm trying to debug WHY they randomly turn unsupported and I don't see anything in the zabbix_server.log. I tried debug level logging but I still don't see anything relating to when a snmp request for an OID fails. The temp probe responds very fast when I try it by snmpget or snmpwalk, but I continue to see "SNMP error [(noSuchName) There is no such variable name in this MIB.]" as the error in the interface when it goes "unsupported". Can anyone suggest where zabbix might tell me something about this?

thanks
-zac

[Alexei]

The temp probe responds very fast when I try it by snmpget or snmpwalk, but I continue to see "SNMP error [(noSuchName) There is no such variable name in this MIB.]" as the error in the interface when it goes "unsupported". Can anyone suggest where zabbix might tell me something about this?

I'm also very interested in understanding why this happens. I believe that
this may happen during initialisation (shutdown/startup) of a SNMP agent.
Perhaps better solution could be setting of an item status to Not Available first, and then, if this is still the case within say 30 minutes, to Not Supported.

What do you think?

[elkor]

Given the nature of SNMP, it's my opinion that the default non-active state should be "not available" with "not supported" only available as a user selected state (which kind of makes it moot as you can always change the item to not monitored).

This of course does leave the application open to being overloaded with configured items that it must retry and may never become available, but it puts the burden on the user to watch their individual configuration more carefully if they choose to utilize monitoring via SNMP.

As it stands now, there are just too many ways that any particular SNMP item can drop into "not supported" and thus be in need of a manual restart; changing the incative state to "not available" solves most, if not all, of these issues.

[Alexei]

As it stands now, there are just too many ways that any particular SNMP item can drop into "not supported" and thus be in need of a manual restart; changing the incative state to "not available" solves most, if not all, of these issues.

I agree. This will hopefully be addressed in 1.1beta4.

[zac]

I'm also very interested in understanding why this happens. I believe that
this may happen during initialisation (shutdown/startup) of a SNMP agent.
Perhaps better solution could be setting of an item status to Not Available first, and then, if this is still the case within say 30 minutes, to Not Supported.

What do you think?

I'm more interested in not changing the status at all. While the addition of Not Available and a retry is good, it's really a bandage, not a solution to the failed query. I'm not getting a "failed to connect" but a "There is no such variable name in this MIB", which indicates that zabbix asked for the wrong thing or I'm dropping bytes in the request. I'd rather just have a monitor go to "Not Available" or "UnSupported" when it really is, but the error doesn't indicate that, it indicates a transmission error. At the moment I'm of the opinion that finding the cause of the state change is more important then what we change it to. maybe an "inError" State to indicate that the value was not returned but we did make a connection.


ahha, in the time it took to write this.. I got a state change.
007405:20051208:143319 Error in packet
Reason: (noSuchName) There is no such variable name in this MIB.

007405:20051208:143319 Parameter [Sensor3-F] is not supported by agent on host [avtech]

007405:20051208:143323 Error in packet
Reason: (noSuchName) There is no such variable name in this MIB.

007405:20051208:143323 Parameter [Sensor2-H] is not supported by agent on host [avtech]

so from this I see that checks_snmp.c has the code but I don't understand the logic.

279 if (status == STAT_SUCCESS)
280 {
281 zabbix_log( LOG_LEVEL_WARNING, "Error in packet\nReason: %s\n",
282 snmp_errstring(response->errstat));

I'm reading this as "if status = STAT_SUCCESS" which I can't find where that is being set.....oh hell..is there a dev list I should be using now?



thanks
-zac

[Alexei]

I'm reading this as "if status = STAT_SUCCESS" which I can't find where that is being set.....oh hell..is there a dev list I should be using now?

It goes in else after:

if (status == STAT_SUCCESS && response->errstat == SNMP_ERR_NOERROR)

so basically it will be true when errstat is equal to SNMP_ERR_NOERROR