How many hours, days, or weeks of trace history does your site want to keep? The minimum recommended trace history is four hours; however, a longer trace history gives a greater span both forward and backward in time. Your choice of a trace history interval falls into one of the following categories:

Short-term trace history

One to two days is typically considered a short-term trace history interval. Short-term trace histories can be obtained without using generation data groups (GDGs).

Long-term trace history

Two or more days is typically considered a long-term trace history interval. Long-term trace histories are best implemented with the use of generation data sets (GDSs) appended sequentially to form a generation data group (GDG).

A long-term trace history is preferred because some DFSMShsm processing (weekly dumps for instance) occurs only on a periodic basis. The longer the trace history, the more obvious is the context within which you can perform problem analysis.