Filter
Top Products
3
Final System Test on OS/390
Just before you migrate to OS/390, you should run all your important
applications in parallel, using the same environment as above. Compare
the results of both systems to make certain there are as few surprises as
possible.
4
Final Production Cut-Over to OS/390 (″D″ Day?)
When you finally migrate your production applications to OS/390, you will
need a backup VSE system standing by for emergency rerun of applications
that uncover any conversion problems after you go live.
┌──────────────┐ ┌──────────────┐ ┌──────────────┐
│ OS/390 │ │ VSE │ │ OS/390 │
│ Production │ │ Stand-By │ │ Maintenance │
││││││
└──────────────┘ └──────────────┘ └──────────────┘
5
After Production Cut-Over to OS/390
Once you are in production, you still need an on-going test system
environment for applying maintenance, and testing new releases of OS/390
and subsystems.
Even after the migration is complete, you will still want to keep a backup
VSE system around for emergency, but this requirement will fade over time.
┌──────────────┐ ┌──────────────┐ ┌──────────────┐
│ OS/390 │ │ OS/390 │ │ VSE Backup │
│ Production │ │ Maintenance │ │ │
││││││
└──────────────┘ └──────────────┘ └──────────────┘
26.3 VM, LPAR, or Standalone Systems
Now that we have sketched briefly the number and types of operating system
images that will be involved in this migration, we need to consider a very
important question. What is the best way to implement these multiple system
images for the migration period, and perhaps into the future given the need for
test and backup OS/390 systems? When considering implementation of multiple
system images the following set of choices exist:
•
Separate hardware platform for each system image (included here would be
consideration of using P/390s to support single system images)
•
Physical partitioning of a single or multiple hardware platforms
•
Logical partitioning of a single or multiple hardware platforms
•
Software partitioning of a single or multiple hardware platforms
•
Some combination of the above choices
The choice you make from the above set depends on many variables such as:
your current hardware environment, the hardware environment you may be
migrating to, your current and future software environment, the physical space
you have available for hardware, your hardware and software budget, the skill
set of your I/T staff, and so on. Each of the choices listed above has positive and
negative aspects depending upon how your environment maps to the variables
described. It would be possible to enter into a lengthy discussion of how to
Chapter 26. Test Environments 421