OMEGAMON XE For DB2 has a Near Term History (NTH) function that is one of the more popular and useful features of the tool. In NTH you can go back in time and look at detailed historical information at the DB2 subsystem (Statistics) and/or the DB2 application (Accounting) level. This is essential information for being able to analyze performance issues after the fact.
DB2 Accounting records, in particular, have the potential to consume a fair amount of DASD space. The records themselves are large, and DB2 may generate many of them, as many as millions a day in many shops. How far back in time you can go in NTH is a function of how many records you need to store, and how much space you allocate in the NTH collection files.
One little known aspect of NTH is that you have the ability to allocate and use more than the three collection datasets you get by default. It used to be you could go up to ten datasets. Now with recent enhancement, you can go up to twenty history collection datasets. This allows for even more storage space, and the ability to keep more history data online.
For more information on this enhancement, check out this link: