Sizing Log Streams for IMS Summary Data Records

This sample table sizes log streams for IMS summary data records:

RetPd Days	Avg Rec Length	Hourly Count	Total Byte Requirement	Max Dsns	4-KB Blocks	Cyls
5	520	10000	624,000,000	100	1,523	8
5	520	50000	3,120,000,000	100	7,617	37
5	520	100000	6,240,000,000	120	12,695	62

Consider the following:

Hourly Count
This count equates to the average number of IMS region termination events that execute per hour. The region summary region is written when an IMS region terminates.

This figure applies to message, BMP and DBT region types. If the average daily total is known, divide the average daily total by 24 to obtain the hourly value. If the data from multiple IMS control regions get logged to the log stream, then this value must be the combined total for those IMS regions.
The IMS Region Summary log stream usually contains a large volume of data and gets written to at a high rate.
Size the offload data sets so each data set contains one-day or less worth of data.