uniform in size.”

The SLA

Related to the standard work unit is the notion of a service-level agreement or SLA. An
SLA is an agreement stating what amounts to an acceptable level of performance and
service in the online transaction environment.

A typical SLA might look like the following:

Mon–Fri, between the hours of 7:30 a.m. and 5:30 p.m.

All transactions will execute in no more than 3 seconds.

There will be no outages of greater than 5 minutes.

The SLA covers both average response time and system availability. The SLA covers
only working hours. Outside working hours, the computer operation staff is free to do
whatever is needed to be done to the computer—running large statistical programs, doing
maintenance, running database utilities, and so forth.

Chapter 7.2: The Standard Work Unit