WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

Operating system based clustering
The WebSphere Application Server high availability framework provides
integration into an environment that uses other high availability frameworks, such
as operating system-based clustering software like HACMP on AIX, or parallel
sysplex on z/OS, to provide high availability for resources for which WebSphere
does not provide specific high availability functions. Consider such a technique
for WebSphere Application Server components such as a deployment manager,
node agents, single server environments, and so on.
5.1.2 Disaster recovery
The main considerations in disaster recovery planning are how to bring up a fully
operative environment after a disaster struck the system, how much data loss
you can afford, and how can ensure that your data remains consistent.
Cluster isolation 1 , for example, is a potential threat to your data consistency and
must be avoided in all circumstances. After the data consistency issues are
resolved (meaning that your problems regarding your WebSphere data, such as
configuration repository, logs and so forth are also resolved) you can resume
your planning for WebSphere disaster recovery.
Note: A design approach to spread your WebSphere Application Server cell
over multiple data centers is not a sufficient response to a disaster recovery
design challenge. Refer to the developerWorks article Everything you always
wanted to know about WebSphere Application Server but were afraid to ask --
Part 2, available at the following Web site:
http://www-128.ibm.com/developerworks/websphere/techjournal/0512_col
_alcott/0512_col_alcott.html
There is no common solution for WebSphere Application Server in a disaster
recovery scenario as this depends on the existing environment, requirements,
applications and budget. For some considerations on disaster recovery in your
WebSphere environment, refer to the Developer works article Everything you
always wanted to know about WebSphere Application Server but were afraid to
ask, Part 5, available at the following Web page:
http://www.ibm.com/developerworks/websphere/techjournal/0707_col_alcott
/0707_col_alcott.html
1 Cluster isolation in this context means a condition that each member of a clustered system
considers the other to be gone and therefore taking over the service. The result would be to have
two systems manipulating data.
Chapter 5. Topologies 125