Saturday, March 8, 2008

ITM 6.1 TDW Summarization and ODI Behavior

The ODI files define the behavior definitions of all of the attributes in the ITM 6.1 EIB (Enterprise Information Database).

The behavior types described in the ODI files affect how summarization works in the TDW (i.e., the _H, _D,... Tables). Count is a special behavior definition that uses delta based summarization (see ITM 6 Admin guide page 63-64). The problem with count is that a lot of agent developers thought it was just a plain old counter field and defined it as such. However when these attributes get aggregated by the SPA the results can get skewed if they are not suppose to be delta based. Count attributes are supposed to be only used for increasing values that occasionally reset (e.g., system uptime). When the next value is lower than the previous value it assumes a reset occurred. This may produce skewed data for pure counter attribute values (e.g. values that fluctuate ... 90, 70, 92, 65 ...). IMHO, there are more than a few attributes defined in the ODI that should not have been defined as count values.

This is taken from my TUG presentation:

Object Behavior Definitions

Gauge - range based numeric
min, max, avg, sum

Count - increasing values w/resets
tot, hi, low, lat

Property - Rarely changing values

Peak - High water mark

Low - Low water mark


Example (Gauge)
'Linix_CPU_H???????????????/System_CPU attribute


Example (Count)

LAT_ System_Uptime

For the full presetation see:

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