In chapter 7 of the manual, DFSMSdfp Storage Administration, it clearly states that changes to data class attributes are not retroactively applied to existing data sets:
"Not all attributes apply to every data set organization. When SMS allocates a data set, it uses only those data class attributes that have meaning for the given data set organization. SMS saves the data class name for each SMS-managed data set. The actual data class definitions reside in the SCDS. If you alter a data class definition, SMS applies the changes to any new data sets that use the data class after you activate the changed configuration. However, SMS does not retroactively apply your changes to previously allocated data sets." However, this does not appear to be entirely true. For example, it appears that you can allocate a SMS-managed data set using a data class that has a Dynamic Volume Count of 3. Then alter the data class's Dynamic Volume Count to 2. You would expect the data set to able to expand to 3 volumes, since the Dynamic Volume Count was 3 at the time the data set was allocated. However, it was discovered that the data set would only expand to 2 volumes. It appears that I cannot change this attribute without affecting existing data sets. Of course, depending on what you trying to accomplish that could good or bad. I ETR'ed IBM about this. They said that data class changes do not apply to existing data sets; however, some access methods have undocumented features which will may dynamically query data class attributes. At this point, they are not ready to document it. Now, my question, has anyone discovered other attributes or conditions where changing existing data class attributes could affect (good or bad) existing data sets? Previous data sets that will be recalled or restored after the data class change? Don Three rules of work: 1. Out of clutter, find simplicity. 2. From discord, find harmony. 3. In the middle of difficulty lies opportunity. -- Albert Einstein ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
