Virtual Server Technology
Examples using Server Virtualization for Disaster Recovery
Example 1. Basic DR
virtualization.
Two
servers at the production facility, one running Exchange
and a second one running Microsoft SQL Server, are
replicated to two virtual servers running on a single physical
server at the IPR Data Center. The OS and application
configurations on the production and virtual machines are
identical, but the use of virtual server technology has
saved the extra physical hardware.
Example 2: DR virtualization of clusters.
The production
facility is running its Exchange application on a two-server
Microsoft cluster as well as a standalone file server. It
is of course possible to replicate the cluster to a standalone
server, however, if the DR facility is expected to support
production usage for an extended period in the event of a
disaster, providing cluster capability there as well can
make sense. It is also possible to run multiple cluster nodes
as virtual servers on a single physical one, but this would
eliminate most of the value of running a cluster on the DR
site at all. So, in this case, two physical servers are used
to contain the two cluster nodes at the DR site, and we are
still able to consolidate a DR file server on one of them
for some savings.
Example 3: The full
power of virtualization.
Here we illustrate the real power of DR server consolidation
using virtual server technology, simply by scaling up exactly
the same usages that are shown in the previous two examples.
In this case, the production site is running 8 different
applications on 10 physical servers, with two of the
particularly critical applications running on clusters to
increase availability. With powerful servers at the IPR Data
Center, it is reasonable to run 4-5 applications per
server, particularly since each of the servers is running
one passive node of a cluster during normal operation. With
the proper distribution of applications, we are able to provide
DR capability for 10 physical production servers on only
3 physical DR servers and still offer clustering on the DR
site with each cluster pair split across physically separate
servers.
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