Beginning Oracle Database 11g Administration From Novice to Professional

CHAPTER 4 PLANNING 73
with standby technology and uses identically configured primary and secondary sites;
in other words. The primary and standby databases both have the same number of RAC
nodes.
MAA can be extended to the application tier too; the details are in the white paper
listed at the end of this essay. Of course, identically configured primary and secondary
sites (both database and application tiers) can be extremely expensive.
Sizing
The hardware resources your database needs depend on a number of factors such as the
characteristics of the application (for example, OLTP vs. OLAP), the expected amount
of activity, and the performance targets (such as the response time of business-critical
transactions). However, it is rare to get good information on the expected amount of
activity; ask how many simultaneously active sessions can be expected on average and
you might get a blank stare in return. Even if you have good information, sizing can still
be tricky. Here are some strategies that you can use:
experience in hardware sizing.
prise
may own several brands, each of which has a similar e-commerce database.
guess” and additional hardware might have to be procured once the initial results
are in.
use this strategy if the application is critical to the enterprise; in such cases it is
preferable to be oversized than undersized.
tem
can accommodate more CPUs and memory if the estimates are found to
be inadequate.
A very good discussion of sizing issues is Sizing Oracle on Microsoft Windows and
Dell PowerEdge Servers by Larry Pedigo (Dell, 2004). The discussion is based on Dell and
Windows but is certainly applicable to other environments. Here are some of the considerations
you should keep in mind when sizing your system.