Information Technology Reference
In-Depth Information
Up to i ve-node clustering is allowed.
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Clustering does not support NIC teaming in the VMs.
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VMs coni gured as cluster nodes must use the LSI Logic SCSI adapter (for Windows Server
2003) or the LSI Logic SAS adapter (for Windows Server 2008) and the vmxnet network
adapter.
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VMs in a clustered coni guration are not valid candidates for vSphere FT or Storage DRS.
They can be part of a cluster that has these features enabled, but the features must be dis-
abled for the VMs participating in the server cluster.
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VMs in a server cluster cannot use N_Port ID Virtualization.
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All the ESXi systems hosting VMs that are part of a server cluster must be running the
same version of ESXi.
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There is something else that you need to do. You must set the I/O timeout to 60 seconds or
more by modifying HKLM\System\CurrentControlSet\Services\Disk\TimeOutValue, and if
you re-create a cluster, you'll need to reset the value again. Additionally, it's a good idea to check
this value on each node when VMware Tools is installed or upgraded.
So, let's get into some more details on clustering and look at the specii c clustering options
available in the virtual environment. We will start with the most basic design coni guration, the
cluster in a box.
Examining Cluster-in-a-Box Scenarios
The cluster-in-a-box scenario involves coni guring two VMs hosted by the same ESXi host as
nodes in a server cluster. The shared disks of the server cluster can exist as .vmdk i les stored
on local Virtual Machine File System (VMFS) volumes or on a shared VMFS volume. Figure 7.4
details the coni guration of a cluster in a box.
Figure 7.4
A cluster-in-a-box
confi guration
does not provide
protection against
a single point of
failure. h erefore, it
is not a common or
suggested form of
deploying Microsoft
server clusters
in VMs.
esxi-05.lab.local
The private network is used for heartbeat
communications between the cluster nodes.
Private network
The public network is how the cluster
communicates with other systems across
the network.
Public network
The cluster nodes have shared connections
to underlying storage.
After reviewing the diagram of a cluster-in-a-box coni guration, you might wonder why you
would want to deploy such a thing. The truth is, you would want to deploy a cluster-in-a-box
coni guration only in certain circumstances because it still maintains a single point of failure.
With both VMs running on the same host, if that host fails, both VMs fail. This architecture
