Chapter 7 of R19 of the Insight System guide documents how the online history files function and gives details on how to estimate their size. For other releases please check the table of content to find the correct chapter as it may varies from release to release.
The history files are standard vsam files, so they can be reorged if needed.
The files should be allocated with 0 secondary space and as the records are written in a "wrap around" manner the files should not actually need reorganizing.
Should there be a need to resize them, the easiest way is to:
1) Stop the Insight datacollector
2) Use the iddcvsam member from the source library supplied,
to create new larger history files.
Run an idcams repro to copy the old history records from the
old vsam files to the new larger vsam files.
3) Rename the old history files to a different name
4) Rename the new history files to the old name
5) Start the Insight datacollector
The new larger sized Online History files will be available.