Practical approach to ISCSI: - My personal views & understanding. - Ashwin

Is I-SCSI an Software Or Hardware ?


Still confused ? , well the answer is, its in both forms, as explained below.

I-SCSI can be thought as client-server architecture.
A "client" (ie: your system - OS) is an initiator, it initiates requests."
A "server" (ie: your storage device - Disks) is a target.

I-SCSI Software Package includes:
1. ISCSI- Initiator (Free download available)
2. ISCSI- Target (Free download available, NOT all vendors)

A software initiator and Target is just a driver that handles all requests and pairs the network interfaces driver and the SCSI drivers together to make it all work.

Bottom Line: There is no cost involved in using a software initiator and Target (Though some Vendors has price tag for target sofware ) . Disadvantage may be: High CPU usage on Host due to processing of TCP/IP + SCSI Commands.


I-SCSI Hardware Package includes:
1. ISCSI- HBA as Initiator as shown in pic above.
2. ISCSI- HBA as Target as shown in pic above.

Hardware Card is nothign but a ethernet card with a SCSI ASIC on-board to offload all the work (TCP/IP + SCSI processing) from the system CPU.

Note: Each iSCSI HBA adapter has two IP addresses: one for SCSI and one for LAN.With iSCSI HBA, TCP/IP and iSCSI protocol processing may be performed on an embedded processor.

Thank You, views from technical gurus are welcome.

FYI: With due courtesy to following sites.
Reference: (Courtesy:http://www.snwonline.com/implement/isci_feasible_04-15-2002.asp)Reference: (Courtesy:http://www.cuddletech.com/articles/iscsi/index.html)
Reference(Courtesy:http://www03.ibm.com/systems/i/
bladecenter/flash/iscsi_systemx_install.swf)