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Monitor change of String attribute

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  • 1.  Monitor change of String attribute

    Posted 05-26-2015 05:09 AM

    Hey there,

     

    Currently I try to find a way to monitor the change of a string-attribute within Spectrum. The attribute is part of a table and I need to monitor all instances.
    From time to time the device mixes up the instances so a specific string from the table suddenly has a new instance-id. So basically were talking about

    an index-shift (well known SNMP issue). Let me make an example:

     

    Time X:

     

    SNMP-OID + InstancemySnmpStringAttribute
    1.3.6.1.4.1.1.100.1.1FirstStringValue
    1.3.6.1.4.1.1.100.1.2SecondStringValue
    1.3.6.1.4.1.1.100.1.3ThirdStringValue
    1.3.6.1.4.1.1.100.1.4FourthStringValue

     

    Time X+1:

     

    SNMP-OID + InstancemySnmpStringAttribute
    1.3.6.1.4.1.1.100.1.1ThirdStringValue
    1.3.6.1.4.1.1.100.1.2FirstStringValue
    1.3.6.1.4.1.1.100.1.3SecondStringValue
    1.3.6.1.4.1.1.100.1.4FourthStringValue

     

    For this example I would need three events for Instance 1, 2 and 3.

    I'm looking for an efficient way to monitor and alarm those changes. I've hundred and more devices which have this issue and the string

    values change from device to device. I thought about using SpectroWATCHes but couldn't figure out a way to solve this. I tried it with

    one watch polling the instances and comparing this to an on-demand watch which would kinda hold the reference values... that did not work.

     

    Has anyone an idea about this? I know SpectroWATCHes are not very strong when it comes to string attributes as the nature of a watch lies more

    in numeric values. At the end I could script something but I rather prefere an out-of-the-box solution with Spectrum.

     

    Thanks a lot for any hint!

     

    Regards,

    Jan Lemmermann



  • 2.  Re: Monitor change of String attribute

    Posted 05-26-2015 03:51 PM

    Are the strings fixed or flexible?  In other words, is FirstStringValue constant relative to itself and when it moves to the wrong index?



  • 3.  Re: Monitor change of String attribute

    Posted 05-26-2015 04:56 PM

    Yes the string is fixed, just the position within the tables changes.



  • 4.  Re: Monitor change of String attribute
    Best Answer

    Posted 05-27-2015 04:13 PM

    I've done something similar with a watch on dskErrorMsg from the ucd-snmp mib disk table.

     

     

    Expression dskErrorMsg.#
    Instance All
    Active By Default No
    Evaluate By Polling every 0 Days + 00:05:00
    Inheritable No
    Threshold Threshold violated if value != dskErrorMsgThreshold .
    Threshold reset if value == dskErrorMsgThreshold .

    dskErrorMsgThreshold is just an empty string.  That works, so there's got to be a way to do what you want.

     

    Maybe take an approach like the time over threshold watches in the documentation?  Or an evaluate on change watch?



  • 5.  Re: Monitor change of String attribute

    Posted 05-28-2015 02:06 PM

    Nevermind the evaluate on change, I played around with that some and it only works with database or memory flagged attributes, so I'm guessing it wont apply here.

     

    I've tried out a couple different variations on this, and while I did manage to get watches to record different values for text string list attributes over time, I couldn't get it to do a reasonable comparison.



  • 6.  Re: Monitor change of String attribute

    Posted 11-04-2015 12:33 PM

    This was extremely helpful.  Thank you for taking the time to answer this.