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But it’s a different story for more complex services, including the following:
• Microsoft Exchange Server
• Microsoft SQL
• MySQL
These servers are more complex to cluster, and although it’s a good idea to have
redundancy in place, if one server goes down, it could take several minutes for the new
server to be transitioned to. This isn’t a virtualization issue; instead, it has to do with
various implementations of clustering software, the complexity of the server, and even
the application software.
These servers can be virtualized, however, if the service is transferred to a secondary
physical server. But for it to work properly, the memory must be constantly synchronized so
a switchover will be unnoticeable to users.
Server Virtualization Solutions
Server virtualization has picked up steam in the past few years, and plenty of companies
are offering their own solutions. In this section, we’ll take a look at two of the most
prevalent companies—VMware and Microsoft—and talk about their solutions.
VMware Infrastructure 3
VMware is the big dog on the virtualization block. The company offers a number of
applications for various virtualization needs and enhancements. Its flagship offering, however,
is VMware Infrastructure 3. The suite comes in three editions: Starter, Standard, and Enterprise.
Link 12-1 will get you over to VMware’s server virtualization section of the VMWare website.
Let’s take a look at the components and technologies in VMware Infrastructure 3.
VMware ESX Server
ESX Server is a virtualization layer that abstracts processor, memory, storage, and networking
resources into multiple virtual machines. It virtualizes server storage and networking,
allowing multiple applications to run in virtual machines on the same physical server.
ESX Server is also available as ESX Server 3i, which offers the same functionality as
the original ESX Server, but with only a 32MB footprint.
VMware VMFS
The file system at the heart of VMware Infrastructure is the VMware Virtual Machine File
System (VMFS). It is a high-performance cluster file system that allows multiple installations
of ESX Server to access the same virtual image. This technology makes it possible for multiple
users to access the same server image simultaneously.
VMware Virtual SMP
Processing performance is enhanced by VMware Virtual Symmetric Multi-Processing (SMP)
technology. This allows a single machine to use multiple processors simultaneously.
VMware VirtualCenter
Management of the suite is done through VMware VirtualCenter. This provides centralized
management, operational automation, and resource optimization to IT environments.