Its been four years since my esteemed colleague, Robert, asked this question about "phased maintenance". He wanted to understand the experiences of those of you who implement maintenance and new releases within the same sysplex by performing rolling LPAR IPLs across multiple days or weeks.
Since then, very little has changed in our maintenance processes, except we've gotten bigger. Our largest sysplex is approaching a dozen LPARs and its becoming increasingly difficult to implement major maintenance changes in a single evening outage window. We've tip-toe'd into phased maintenance by implementing changes on one or two small special-purpose low-usage systems a few days in advance of making the same changes to the major production systems, which run a variety of transaction and database systems. But, some at our company are still very nervous about implementing this phased maintenance approach on our major production systems, especially when increasingly-restrictive scheduling means this mixed maintenance environment may need to exist for two or three weeks at a time. I understand that IBM provides a multi-release co-existence support policy for z/OS and other ServerPac products, which very adequately covers much of our IBM inventory, and that IBM will fix any problems discovered. But, have you actually encountered any problems caused by co-execution of multiple maintenance levels or releases of IBM software? BTW, IBM transaction and database software is out of the scope of this question for us, because they are maintained separately. In addition, I want to mention that we implement most of our ISV software inventory using the same maintenance philosophy and that's also a concern that may not have been addressed in Robert's original question. I'd appreciate any feedback you can provide on your current phased maintenance implementation experiences, especially when the mixed-maintenance environment coexists for a week or longer on major production systems. Thanks in advance for your feedback. Dennis Schaffer ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
