Using Hardware iSCSI Initiators with ESX/ESXi hosts allows which of the following tasks to be offloaded from the VMkernel?
Issuing SCSI commands to the virtual disk
Encapsulation of I/O requests into iSCSI Protocol Data Units (PDUs)
Encapsulation of iSCSI PDUs into TCP/IP packets
Mapping requests for blocks on the virtual disk to blocks on the appropriate physical device
iSCSI From Wikipedia, the free encyclopedia
An initiator functions as an iSCSI client. An initiator typically serves the same purpose to a computer as a SCSI bus adapter would, except that instead of physically cabling SCSI devices (like hard drives and tape changers), an iSCSI initiator sends SCSI commands over an IP network.
An initiator falls into two broad types:
A software initiator uses code to implement iSCSI. Typically, this happens in a kernel-resident device driver that uses the existing network card (NIC) and network stack to emulate SCSI devices for a computer by speaking the iSCSI protocol. Software initiators are available for most mainstream operating systems, and this type is the most common mode of deploying iSCSI on computers.
A hardware initiator uses dedicated hardware, typically in combination with software (firmware) running on that hardware, to implement iSCSI. A hardware initiator mitigates the overhead of iSCSI [B above] and TCP [A above] processing and Ethernet interrupts, and therefore may improve the performance of servers that use iSCSI.