Seagate ST43401N/ND Guida di Installazione Scaricare il pdf (Pagina 39)

CHAPTER 4 Plan: Writing a Plan and Getting Ready to Migrate

Be sure to account for any increased release 12.5 memory requirements that

apply to your configuration. For more information, see:

•The

installation guide at http://manuals.sybase.com:80/onlinebooks/group-

as/asp1250e/@Generic__CollectionView;pt=asp1250e

for your platform. It

gives basic RAM requirements.

• Chapter 6, “Implement: Making Database Administration Changes”.

• Details on configuring memory and data caches in the

System

Administration Guide at http://manuals.sybase.com:80/onlinebooks/group-

as/asg1250e/sag/@Generic__BookView

• Information on how to configure memory for performance in the

Performance and Tuning Guide at

http://manuals.sybase.com:80/onlinebooks/group-

as/asg1250e/perf/@Generic__BookView

Note For a production system, execute the performance suite during off hours.

Scheduling

Developing and running the replication facility, validation and performance

suite, and fallback script requires significant effort. If your environment

already uses replication, this effort will be notably easier.

For a development system, you may want to add a short period to the

development schedule for release 12.5 issues.

For a production system, be prepared to postpone or back off if needed.

Cutover Without Replication

The issues for the cutover without replication approach are described in the

following sections:

Method

Upgrade all databases to release 12.5 at the same time. A cutover without

replication is common in small organizations for development or production

servers. It may be used in larger organizations when you are able to schedule

sufficient downtime.

Fallback

Base fallback on the amount of time needed to restore earlier databases. For

example, if users need the system Monday at 8 a.m. and the restoration takes 8

hours, the validation test must pass by Sunday at midnight.

Note Remember to include client fallback time in the calculation.

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Seagate ST43401N/ND Guida di Installazione Pagina 39