IBM OS/390 User Manual
Chapter 34. Customer Migration Example
This chapter describes an actual user experience with migration. Since every
customer environment is unique, care should be taken when drawing
comparisons, especially in areas of resource and capacity.
customer environment is unique, care should be taken when drawing
comparisons, especially in areas of resource and capacity.
34.1 Background
Cust1 is a relatively fast growing company that evolved from a small 4341 to a
3-way 9672 in a little more than a decade. The I/S organization was constantly
challenged to support new business with very little lead time. Their VSE
operating system was always being pushed to its limits supporting the growing
workload. The computer operations had grown to a near 21 shift operation (only
a two to four hour window early Sunday morning for maintenance). For five or
six years before the final decision to migrate to MVS, serious consideration was
given to an MVS migration because of the constraints of the VSE architecture on
their business, but new enhancements to VSE relieved the urgency. All of the
measures to improve VSE performance were taken, for example, multiple VSE
guests for parallelism, faster engines, faster DASD, VSE ESA features and so on.
Each time a new piece of business was taken on, the I/S organization was
concerned if they would be able to contain the workload, and usually suffered a
lot of pain balancing resources. Finally it was decided that the move to MVS
would be the only recourse to support the future business growth.
3-way 9672 in a little more than a decade. The I/S organization was constantly
challenged to support new business with very little lead time. Their VSE
operating system was always being pushed to its limits supporting the growing
workload. The computer operations had grown to a near 21 shift operation (only
a two to four hour window early Sunday morning for maintenance). For five or
six years before the final decision to migrate to MVS, serious consideration was
given to an MVS migration because of the constraints of the VSE architecture on
their business, but new enhancements to VSE relieved the urgency. All of the
measures to improve VSE performance were taken, for example, multiple VSE
guests for parallelism, faster engines, faster DASD, VSE ESA features and so on.
Each time a new piece of business was taken on, the I/S organization was
concerned if they would be able to contain the workload, and usually suffered a
lot of pain balancing resources. Finally it was decided that the move to MVS
would be the only recourse to support the future business growth.
34.2 Environment
34.2.1.1 Hardware
•
Bipolar air cooled 3-way processor
•
The customer changed to a 9672 3-way in the middle of the project. This
change was made primarily because of an IBM marketing package that
actually provided more resource for a lower lease cost. This occurred at a
time in the project when the extra capacity (mostly central storage) was very
welcome (systems tests).
change was made primarily because of an IBM marketing package that
actually provided more resource for a lower lease cost. This occurred at a
time in the project when the extra capacity (mostly central storage) was very
welcome (systems tests).
256MB storage
1GB on the 9672
•
RAMAC DASD
Two racks of RAMAC I each 2/3 full (3380)
One rack of RAMAC II 1/3 full (3390)
All racks filled by switchover for testing bubble
34.2.1.2 Software
•
VM/ESA
•
VSE/ESA (three guests)
•
The VSE level with turbo was installed before the project, but the turbo
dispatcher was not enabled because of poor performance and availability
issues.
dispatcher was not enabled because of poor performance and availability
issues.
Copyright IBM Corp. 1998
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