© 2007 Cisco Systems, Inc. E-Commerce Module Design 7-9
People
People are one of the most critical components of high availability.
© 2007 Cisco Systems, Inc. All rights reserved.
ARCH v2.0—7-9
People
Staff work habits and skills matter!
– Attention to detail
– Reliability and consistency
Good skills and ongoing technical training are needed:
– Including lab time working with technology, practical skills, troubleshooting
challenge scenarios, etc.
– Communication and documentation are important.
What other groups expect
Why the network is designed the way it is, how it is supposed to work.
If people are not given the time to do the job right, they cut
corners:
– If the design target is just “adequate”, falling short is poor.
Staff team should align with services.
– Owner and experts for each key service application and other
components.
Redundant equipment and links and advanced technology are just the beginnings of high
availability. In the prepare, plan, design, implement, operate, and optimize (PPDIOO)
methodology, the people component is vitally important as well. Staff work habits and skills
can impact high availability. For example, attention to detail enhances high availability while
sloppiness hurts availability. Reliable and consistent wiring and configurations are easier to
manage and troubleshoot.
The level of staff skills and technical training are also important when it comes to taking full
advantage of redundancy. Devices must be correctly configured. Lab testing is important in
order to understand under what circumstances failover will activate, and what failover will and
will not accomplish. For example, non-stateful firewall failover may be adequate in terms of
passing traffic, a practical understanding of the application can show that with non-stateful
failover. Application sessions will lock up for an extended period of time until an application
timeout causes session re-establishment. Designs including failover must be tested for the entire
system, not just for individual components.
Good communication and documentation are also important. The network administrators need
to be able to communicate with other network, security, application, and server teams. The
network documentation should cover why things are designed the way they are, and how the
network is supposed to work. Failover behavior is complex enough that it is unwise to have to
re-capture failover logic and boundary conditions every time some part of the design changes.
Field experience leads to the observation that if people are not given the time to do the job
right, they will have to cut corners. Testing and documentation are often the first items to be
eliminated. Lack of thorough testing and documentation will have long term consequences on
the ability to maintain, expand, and troubleshoot the network.