| The purpose of iSCSI is simple: make a block storage | | | | physical device, an emulated virtual device is |
| device, such as a disk or a volume, accessible over a | | | | presented. The underlying implementation can deviate |
| mainstream IP network. When iSCSI was introduced | | | | drastically from the presented target as is done with |
| it looked like a nice niche market because 1Gbps | | | | Virtual Tape Library (VTL) solutions. VTLs use disk |
| Ethernet had become the standard baseline for | | | | storage for storing data written to virtual tapes. As |
| network throughput across the board but now | | | | with actual physical devices, virtual targets are |
| 10Gbps Ethernet is a reality. With this faster and | | | | presented by using iSCSI target.software, external |
| wider bandwidth iSCSI and iSCSI targets have been | | | | bridges, or controllers internal to the device enclosure. |
| elevated from a niche tool to be the conventional | | | | All storage protocols, FC, pSCSI, iSCSI have two |
| solution. The immediate benefit of iSCSI is clear: | | | | “ends” in the connection. These ends are the |
| no-cost/low-cost storage networking. The long term | | | | Initiator and the Target. In iSCSI we call them iSCSI |
| advantage of iSCSI is the flexibility it provides as a | | | | Initiator and iSCSI target. The iSCSI Initiator: |
| product of the cost, systems that you would never | | | | Requests, or initiates, any iSCSI communications. It |
| have imagined putting a Fibre Channel HBA in are | | | | requests all SCSI operations like read or write. An |
| now prime candidates for iSCSI and iSCSI target. | | | | initiator is usually located on the host/server side |
| Most industry focus has been placed on creating | | | | (either an iSCSI HBA or iSCSI SW initiator) iSCSI |
| iSCSI target disks though iSCSI tape and medium | | | | target. |
| changer targets are popular as well. So far, physical | | | | : The iSCSI target is the storage device itself or an |
| devices have not featured native iSCSI interfaces on | | | | appliance that controls and serves volumes or virtual |
| a component level. Instead, devices with SCSI Parallel | | | | volumes. The target is the device that performs the |
| Interface or Fibre Channel interfaces are bridged by | | | | SCSI command or bridges it to an attached storage |
| using iSCSI target software, external bridges, or | | | | device. iSCSI targets, like the iSCSI V-Switch, can be |
| controllers internal to the device enclosure. | | | | disks, tapes, RAID arrays, tape libraries, FC Fabrics, |
| Alternatively, disk and tape targets can be | | | | etc. |
| virtualizations. Rather than representing an actual | | | | |