HP 2G Update Manual page 4

ISS Technology Update
drive. The iSCSI stack at both ends of the path is used to encapsulate SCSI block commands into Ethernet Packets for
transmission over IP networks as illustrated in Figure 2-1.
Figure 2-1. iSCSI is SCSI over TCP/IP
File System
Disk Driver
SCSI
SCSI MP**
Direct attached block
storage using
SCSI/SAS *
* Serial Attached SCSI
** Multipathing
Initiators include both software- and hardware-based initiators incorporated on host bus adapters (HBAs) and network interface
cards (NICs). Software initiators require CPU resources to manage the iSCSI protocol stack. A more efficient approach is to
offload the protocol management to a hardware-based iSCSI HBA or NIC. The operating system sees an iSCSI HBA or NIC as
a SCSI device.
Accelerated iSCSI
Traditional software-based iSCSI initiators generate more processing overhead for the server CPU. By contrast, HP accelerated
iSCSI offloads the protocol processing to an HP Multifunction Server Adapter so that CPU utilization is reduced and iSCSI
performance is accelerated. HP Accelerated iSCSI supports all targets that are certified and supported by Microsoft iSCSI
Software Initiator.
ProLiant servers utilizing Accelerated iSCSI Multifunction server adapters show significant improvements in server efficiency over
software-based iSCSI initiators. For more on the performance gains experienced with the Broadcom solution for HP hardware-
assisted iSCSI Multifunction server adapters, read test results from the Tolly Group at
http://www.tolly.com/TS/2008/HewlettPackard/iSCSISolutions/Tolly208305HPiSCSI.pdf.
HP Accelerated iSCSI technical advantages
There are several advantages derived from implementing Accelerated iSCSI:
Standard configurations, including ideal input/output (I/O), read/write, random/sequential and queue sizes
Improved I/O operations per second (IOPS) compared to iSCSI host bus adapters from other vendors
Processing work offloaded to the NIC to free CPU cores for data-intensive workloads
Increased server and IP storage application performance
Increased iSCSI performance
iSCSI initiator
File System
Disk Driver
SCSI
iSCSI MP**
TCP/IP
Ethernet
Ethernet
Ethernet
iSCSI target
iSCSI
TCP/IP
Ethernet
Remote block storage using iSCSI
Volume 8, Number 5
SCSI
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