Initiators
Microsoft provides a free iSCSI software initiator, which can be downloaded from the Microsoft web site. There are other iSCSI initiators available, but this report will only discuss the Microsoft iSCSI software initiator. The focus of this report is primarily on iSCSI targets.
The iSCSI initiator works in combination with the network adapter. There are four basic combinations of iSCSI initiators and network adapters available today. Varying degrees of processing can be offloaded to the adapter hardware, depending on the type of network adapter deployed. These combinations of iSCSI initiator and network adapter are:
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Software iSCSI initiator with standard network card
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Software iSCSI initiator with advanced network card that supports Receive-side Scaling
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Software iSCSI initiator with network card that includes a TCP/IP Offload Engine (TOE)
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Hardware iSCSI host bus adapter (HBA) that provides offloaded TCP/IP and iSCSI processing.
The performance aspects of these types of iSCSI initiators are discussed below in the iSCSI performance section. The hardware iSCSI HBAs were not tested for this report but they do help to optimize CPU utilization in servers.
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