Support for iSCSI technology components in Exchange Server

This article discusses Internet small computer system interface (iSCSI). This article discusses iSCSI compatibility and iSCSI support in Microsoft Exchange 2000 Server and in Microsoft Exchange 2003 Server.

iSCSI overview

iSCSI is an Internet Protocol-based (IP-based) method that is designed to send small computer systems interface (SCSI) commands that are encapsulated in IP packets over TCP/IP networks. Users and applications request and receive data from high-performance data storage devices over standard network switches and over IP routers. Because iSCSI is IP-based, data can be transmitted over local area networks (LANs), over wide area networks (WANs), and over the Internet to remote storage locations. Microsoft operating systems display iSCSI hard disks to users and to programs such as Exchange Server 2003 or Exchange 2000 Server as hard disks that are connected directly to the user's computer.

iSCSI deployment

Microsoft encourages you to use caution when you deploy Exchange Server 2003 with iSCSI or Exchange 2000 Server with iSCSI. Because iSCSI uses the SCSI transport protocol to transmit block data over TCP/IP networks, the involvement of a network can introduce components that are not traditionally thought of as high-speed input/output paths. To maximize , make sure that the networking components that are involved in the data path are suited for high bandwidth iSCSI disk transfers. To make sure that bandwidth is reliably available for disk transfers, we also recommend that you do not share the disk I/O path with other network traffic.

Hardware selection

If the fibre channel storage area network (SAN) hardware or the iSCSI SAN hardware has passed the Designed for Windows Logo Program for iSCSI hardware devices, the hardware is also supported by Exchange Server 2003 and by Exchange 2000 Server. In other words, no additional qualification for Exchange Server 2003 or for Exchange 2000 Server is provided under the Designed for Windows Logo Program. You can view hardware components that are qualified under the Designed for Windows Logo program for Microsoft Windows 2000 and for Microsoft Windows Server 2003 in the Windows Server Catalog. For more information about the Windows Server Catalog, visit the following Microsoft Web site: For more information about support for direct attached storage (DAS), network attached storage (NAS), or storage area networks (SANs) in Exchange Server, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft requires that storage systems for Exchange Server data on clustered servers be qualified for cluster implementations and designed to support Exchange Server data. A storage system that performs well in a non-clustered environments may not be suitable for use in a cluster. If you plan to use SAN or iSCSI solutions in clustered Exchange environments, Microsoft strongly recommends that you verify that the complete clustering solution has passed the Microsoft Cluster Hardware Compatibility Test (HCT) testing and received the “cluster qualified” solution logo. If you combine individual components and devices, Microsoft does not guarantee that the specific arrangement is supported in a clustered configuration. This is true even if all individual components are listed in the Windows Server Catalog.

Microsoft also recommends that you consider specific functionality requirements when you select your hardware. For example, online snapshot backup is supported when you use the Volume Shadow Copy service on iSCSI hardware that has an appropriate Volume Shadow Copy service hardware provider. For more information about the Volume Shadow Copy service, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to configure clustered Exchange servers, click the following article number to view the article in the Microsoft Knowledge Base: For more information about iSCSI hardware that has passed the Designed for Windows Logo Program, visit the following Microsoft Web site: Microsoft recommends that you use Gigabit Ethernet. Gigabit Ethernet has error rates that are similar to fibre channel. If your storage area network (SAN) that supports your Exchange environment uses fibre channel or iSCSI, Microsoft recommends that you contact your SAN storage vendor for performance and configuration recommendations.

Hardware performance evaluation

Microsoft recommends that you use Microsoft-provided performance evaluation tools such as Jetstress to test your DAS configuration, SAN configuration, or NAS configuration to verify that the configuration meets performance requirements.

For more information about Jetstress, visit the following Microsoft Web site:

Microsoft iSCSI Initiator service

Persistent targets are devices that are identified by the same IP or by media access control (MAC) address in each session. The use of persistent targets requires that Exchange services are dependant on the Microsoft iSCSI Initiator service (msiscsi). The Initiator service is a service that manages all iSCSI initiators, including network adapters and host bus adapters (HBAs) on behalf of the operating system. The iSCSI Initiator service aggregates discovery information and manages security.

To make the volumes persistent, Microsoft recommends that you use the iSCSI command line interface (ISCSICLI) command persistentlogintarget or the iSCSI Initiator Control Panel tool. To permit the iSCSI service to configure the list of persistent volumes, you can use the ISCSICLI command bindpersistentvolumes or the iSCSI Initiator Control Panel tool.

Note If you make any services dependent upon the Microsoft iSCSI initiator service, you must manually stop the service before you upgrade or remove the Microsoft iSCSI initiator package.

Additional information

Exchange 2007: Storage Technology
http://technet.microsoft.com/en-us/library/bb738146(EXCHG.80).aspx (http://technet.microsoft.com/en-us/library/bb738146(EXCHG.80).aspx)

Exchange 2010: Understanding Storage Configuration
http://technet.microsoft.com/en-us/library/ee832792.aspx (http://technet.microsoft.com/en-us/library/ee832792.aspx)

For more information about iSCSI technology and Microsoft support of iSCSI, visit the following Microsoft Web site: