Creating a Failover Cluster
Creating
a failover cluster is a multistep process. The first step is to
configure the physical hardware for the cluster. Then, you need to
install the Failover Clustering feature and run the Failover Cluster
Validation Tool, which ensures that the hardware and software
prerequisites for the cluster are met. Next, once the configuration has
been validated by the tool, create the cluster by running the Create
Cluster Wizard. Finally, to configure the behavior of the cluster and
to define the availability of selected services, you need to run the
High Availability Wizard.
Preparing Failover Cluster Hardware
Failover
clusters have fairly elaborate hardware requirements. To configure the
hardware, review the following list of requirements for the servers,
network adapters, cabling, controllers, and storage:
Servers Use a set of matching computers that consist of the same or similar components (recommended).
Network adapters and cabling
The network hardware, like other components in the failover cluster
solution, must be compatible with Windows Server 2008. If you use
iSCSI, each network adapter must be dedicated to either network
communication or iSCSI, not both.
In
the network infrastructure that connects your cluster nodes, avoid
having single points of failure. There are multiple ways of
accomplishing this. You can connect your cluster nodes by multiple,
distinct networks. Alternatively, you can connect your cluster nodes
with one network constructed with teamed network adapters, redundant
switches, redundant routers, or similar hardware that removes single
points of failure.
Device controllers or appropriate adapters for the storage
If you are using serial attached SCSI or FC in all clustered servers,
the mass-storage device controllers that are dedicated to the cluster
storage should be identical. They should also use the same firmware
version. If you are using iSCSI, each clustered server must have one or
more network adapters or HBAs that are dedicated to the cluster
storage. The network you use for iSCSI cannot be used for network
communication. In all clustered servers, the network adapters you use
to connect to the iSCSI storage target should be identical. It is also
recommended that you use Gigabit Ethernet or higher. (Note also that
for iSCSI, you cannot use teamed network adapters.)
Shared storage compatible with Windows Server 2008
For a two-node failover cluster, the storage should contain at least
two separate volumes (LUNs), configured at the hardware level.
The first volume will function as the witness disk, a volume that holds a copy of the cluster configuration database. Witness disks, known as quorum disks in Microsoft Windows Server 2003, are used in many but not all cluster configurations.
The second volume will contain the files that are being shared to users. Storage requirements include the following:
To use the native disk support included in failover clustering, use basic disks, not dynamic disks.
It is recommended that you format the storage partitions with NTFS. (For the witness disk, the partition must be NTFS.)
When
deploying a storage area network (SAN) with a failover cluster, be sure
to confirm with manufacturers and vendors that the storage, including
all drivers, firmware, and software used for the storage, are
compatible with failover clusters in Windows Server 2008.
After
you have met the hardware requirements and connected the cluster
servers to storage, you can then install the Failover Cluster feature.
Note: What is the quorum configuration?
The quorum configuration
in a failover cluster determines the number of failures that the
cluster can sustain before the cluster stops running. In Windows Server
2008, you can choose from among four quorum configurations. The first
option is the Node Majority quorum configuration, which is recommended
for clusters with an odd number of nodes. In node majority, the
failover cluster runs as long as a majority of the nodes are running.
The second option is the Node and Disk Majority quorum configuration,
which is recommended for clusters with an even number of nodes. In node
and disk majority, the failover cluster uses a witness disk as a
tiebreaker node, and the failover cluster then runs as long as a
majority of these nodes are online and available. The third option is
the Node And File Share Majority quorum configuration. In node and file
share majority, which is recommended for clusters that have an even
number of nodes and that lack access to a witness disk, a witness file
share is used as a tiebreaker node, and the failover cluster then runs
as long as a majority of these nodes are online and available. The
fourth and final option is the No Majority: Disk Only quorum
configuration. In this configuration, which is generally not
recommended, the failover cluster remains as long as a single node and
its storage remain online.
Installing the Failover Clustering Feature
Before creating a failover cluster, you have to install the Failover Clustering feature on all nodes in the cluster.
To
install the Failover Clustering feature, begin by clicking Add Features
in Server Manager. In the Add Features Wizard, select the Failover
Clustering check box. Click Next, and then follow the prompts to
install the feature.
Once the feature is installed on all nodes, you are ready to validate the hardware and software configuration.
Validating the Cluster Configuration
Before
you create a new cluster, use the Validate A Configuration Wizard to
ensure that your nodes meet the hardware and software prerequisites for
a failover cluster.
To
run the Validate A Configuration Wizard, first open Failover Cluster
Management Administrative Tools program group. In Failover Cluster
Management, click Validate A Configuration in the Management area or
the Actions pane, as shown in Figure 5.
After
the wizard completes, make any configuration changes if necessary, and
then rerun the test until the configuration is successfully validated.
After the cluster prerequisites have been validated, you can use the
Create Cluster Wizard to create the cluster.
Running the Create Cluster Wizard
The
next step in creating a cluster is to run the Create Cluster Wizard.
The Create Cluster Wizard installs the software foundation for the
cluster, converts the attached storage into cluster disks, and creates
a computer account in Active Directory for the cluster. To launch this
tool, in Failover Cluster Management, click Create A Cluster in the
Management area or Actions pane.
In
the Create Cluster Wizard, simply enter the names of the cluster nodes
when prompted. The wizard then enables you to name and assign an IP
address for the cluster, after which the cluster is created.
After
the wizard completes, you need to configure the services or
applications for which you wish to provide failover. To perform this
aspect of the configuration, run the High Availability Wizard.
Running the High Availability Wizard
The
High Availability Wizard configures failover service for a particular
service or application. To launch the High Availability Wizard, in
Failover Cluster Management, click Configure A Service Or Application
in the Action pane or Configure area.
To complete the High Availability Wizard, perform the following steps:
1. | On the Before You Begin page, review the text, and then click Next.
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2. | On
the Select Service Or Application page, select the service or
application for which you want to provide failover service (high
availability), and then click Next.
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3. | Follow
the instructions in the wizard to specify required details about the
chosen service. For example, for the File Server service, you would
need to specify the following:
A name for the clustered file server Any
IP address information that is not automatically supplied by your DHCP
settings—for example, a static IPv4 address for this clustered file
server The storage volume or volumes that the clustered file server should use
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4. | After the wizard runs and the Summary page appears, to view a report of the tasks the wizard performed, click View Report.
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5. | To close the wizard, click Finish.
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Testing the Failover Cluster
After
you complete the wizard, test the failover cluster in Failover Cluster
Management. In the console tree, make sure Services and Applications is
expanded, and then select the service you have just added with the High
Availability Wizard. Right-click the clustered service, click Move This
Service Or Application To Another Node, and then click the available
choice of node. You can observe the status changes in the center pane
of the snap-in as the clustered service instance is moved. If the
service moves successfully, the failover is functional.
