Server cluster support for Windows Storage Server 2003 network attached storage devices

This article discusses support issues that you may want to consider when you use a network-attached storage device in a clustered environment.

The Microsoft Windows Storage Server 2003 feature pack includes support for Microsoft Exchange Server data on a Windows Storage Server-based network-attached storage device. However, this new feature has raised questions about using this feature in a clustered environment.

When network-attached storage provides "file share" storage functionality to computers in a server cluster, the network-attached storage is not considered to be a "shared storage device" according to the Windows Clustering definition of such a device.

Windows Clustering Microsoft Windows Hardware Quality Labs (WHQL) requires that shared storage devices such as direct attached storage (DAS), storage area network fibre channel, or SAN-iSCSI devices be included with the hardware configuration when this hardware configuration is submitted to WHQL. These shared storage technologies provide block storage to one or more of the cluster nodes. Therefore, cluster failover services must be tested on these configurations.

However, network-attached storage is just a network file share service that is provided to one or more of the computers in a server cluster. Cluster WHQL does not specify requirements for file shares that are accessed on the network, whether these file shares are used for typical file data or for Exchange data. Therefore, you can take any existing WHQL-qualified configuration and deploy it by using network file shares for user data.

Note In this scenario, you must still follow any specific considerations that are required by the clustered program that you want to run. For example, you must consider additional requirements when you run Exchange Server in a clustered environment.

Important The cluster quorum resource cannot be located on a file share that is provided by a computer that is not part of the server cluster. Therefore, a Windows Storage Server-based network-attached storage cannot host the cluster quorum resource. The cluster quorum resource must be provided by a DAS device, a storage area network block disk, or by the cluster majority node set (MNS).

Clustered Exchange deployments

If you use Exchange Server in a clustered environment together with Windows Storage Server-based network-attached storage file shares to store your Exchange Server database files or transaction log files, consider the following limitations and requirements.

Exchange Server instance limitations

You can have a maximum number of two Exchange Server instances for each network-attached storage device. In this scenario, you can configure any one of the following environments with the NAS device:

• One Active/Active cluster
• Two Active/Passive clusters
• Two stand-alone non-clustered Exchange servers
• One Active/Passive cluster and one stand-alone Exchange server

Exchange Server network requirements

When you store your Exchange Server database files or transaction log files on the network-attached storage device, you must have a Gigabit Ethernet network adaptor for each Exchange Server-based computer. In this scenario, we recommend that each network adaptor be connected to different ports of a Gigabit switch.

Note The amount of network bandwidth that you must have is almost completely dependent on Exchange Server usage patterns. Typically, during peak usage periods, 300 users who access Exchange at the same time will over-stress a 100 megabit connection. In this scenario, if network bandwidth becomes unavailable, Exchange Server may dismount the information store databases to help prevent data loss. Therefore, we recommend that you have additional network bandwidth available.

Exchange Server storage considerations

We recommend that you do not store the Exchange Server transaction log files on the same volume as the database files. If you store the transaction log files and the database files on different volumes, you have a larger chance of recovering Exchange Server from a failure.

For additional information about how to manage Exchange storage by using the Windows Storage Server 2003 feature pack, visit the following Microsoft Web site: For additional information, click the following article number to view the article in the Microsoft Knowledge Base: For additional information about Windows Storage Server, visit the following Microsoft Web site:

For more information, click the following article number to view the article in the Microsoft Knowledge Base: