Sizing Log Streams for IMS Transaction Data Records

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

RetPd Days	Avg Rec Length	Hourly Count	Total Byte Requirement	Max Dsns	4-KB Blocks	Cyls
5	450	10000	540,000,000	100	1,318	7
5	450	50000	2,700,000,000	100	6,592	32
5	450	100000	5,400,000,000	120	10,986	53

Consider the following:

Hourly Count
This count equates to the average number of IMS transactions that execute per hour. 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 gets logged to the log stream, then this value must be the combined total for those IMS regions.
The IMS Transaction 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.