Top-Level Service Level Agreement
TDT4285 Computer Systems — Design and Operation
January 17, 2008
This agreement describes the service level for the system as a whole. The service
level for speciﬁc services/subsystems is deﬁned in the service level agreements
for those services.
The service provieder is the class, and the course staﬀ is the customer.
The system shall be available 24/7 from March 14, 2008, until April 24, 2008,
Maintenance windows shall be placed between 08:00 and 16:00 on a working
day, and the provider shall give notice at least 24 hours prior to start. Notice is
given by sending an e-mail to email@example.com with a description of
planned changes and expected downtime (from–until). The provider shall give
notice by the same methods when the system is available again.
One such maintenance window of maximum 5 hours is allowed within the
A subsystem is available if it can be accessed and works according to the ser-
vice level agreement. The system as a whole is available if all subsystems are
The service provider shall attempt at 99.9% uptime for each service.
The service provider shall document the uptime of their services, and shall
report the achieved uptime at the end of the period. This report shall show
when the system has been available and the achieved uptime in percentage of
When computing uptime, downtime within a correctly announced mainte-
nance window is excluded.
A more detailed deﬁnition of uptime and uptime monitoring requirements
can be deﬁned in subsystem service level agreements.
Service interruptions are not allowed outside correctly announced maintenance
windows. The service provider shall monitor the system to make sure interrup-
tions are discovered and dealt with.
Performance requirements are deﬁned for each subsystem in the corresponding
service level agreement.
The service provider is contacted by sending e-mail to firstname.lastname@example.org. If
the request is posted before 12:00 on a school day, the service provider shall
respond within the same day. Other request shall be responded to within the
next school day.
The response to a request shall conﬁrm that the problem is ﬁxed or a time
when the problem will be ﬁxed. The service provider shall make an attempt at
solving 90% of the problems within the response time.
The service provider shall provide statistics of request handling at the end
of the operation period.
The service provider shall follow good change management practice, and change
management documentation shall be provided at the end of the operation pe-
The service provider shall make sure that the system is secured and adheres to
IDI and NTNU IT regulations.
All services are oﬀered for free! :-)
Changes to this Agreement
Changes to this agreement can be made in meetings on Thursdays between 14:00
and 16:00 if such a change has been announced at least 48 hours in advance.
Changes are only valid if the majority of groups present agree on them and
the course staﬀ approves them, or if the course staﬀ decides to change them
without the groups’ consent. :-)