Because of past conversions, I think this needs to be said: 1) VSE/ESA got to use XA I/O just like MVS. This means, to the VSE shop, that some slick stuff that got offloaded to the I/O Subsystem (shall we say parts of VM's and MVS' I/O Supervisor code) became available w/o any JCL or application coding changes. Things like dual (or multi) pathing with dynamic pathing.
What does this have to do with anything? Well, the typical throughput performance gains seen in the past when going from VSE to MVS don't happen because what was giving those (for the most part) has already been realized. 2) VSAM is implemented in VSE differently than in MVS. So, the way sharing and buffer management is done changes and WILL cause performance issues when you get to MVS. 3) CICS is impacted by these changes, and you may see less throughput. Although, with the ability to have more storage than z/VSE allows, you may over come it. But be sure to have sufficient page volumes. Bottom line: To get the same or better performance from a well tuned VSE shop that goes to MVS, you will need people who are well versed in all the tricks. And they will need to understand what was happening on the VSE system to effect similar results on the MVS system. Regards, Steve Thompson -- Opinions expressed by this poster may not reflect those of poster's employer. -- ---------------------------------------------------------------------- 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
