Are iSCSI and InfiniBand in Your Storage Future?
These days, storage still revolves mostly around fiber channel (FC) on the higher end and SCSI on the lower end. Over the next year or two, though, emerging approaches like InfiniBand and iSCSI are expected to make bigger inroads. What will these new technologies mean for network administration?
FC will keep holding a lot of industry sway because of its large existing installed base, panelists agreed, during a conference session at Fall Comdex entitled "Anticipating the Multi-Protocol World: Storage over IP, InfiniBand, Advances in Fibre Channel and Beyond."
"Fiber channel is very well established on the high end. Fiber channel demand is at a premium," according to Bob Hansen, director of strategic business development for Agilent Technologies.
In the future, however, FC, InfiniBand and ISCSI "will all be successful in their own ways," Hansen predicted.
Unlike FC, which requires a separate fiber optic network, iSCSI runs over standard IP and Ethernet. Joe Gervais, director of product marketing for Alacritech Inc., foresees a big burst of activity next year, when Microsoft is expected to release an ISCSI service pack for standard NICs.
"That will drive a lot of rapid adoption," according to Gervais. "One of the big visions is video-on-demand, (with) computers being used to process data."
Advantages of iSCSI include IP- and Ethernet-based management, higher scalability, and the ability to do remote backup and database replication over longer distances than SCSI, said Kevin Deirling, VP of marketing for Mellanox.
"iSCSI simplifies (management)," Deirling maintained. "IT expertise on IP is already there, (and iSCSI) is a portion of existing network management."
"Everybody has to manage Ethernet (already). Everybody has to manage storage," Hansen concurred. Meanwhile, Ethernet speeds will start to rise to 40 gigabits-per-second, he says.
Also under PC, FC host bus adapters must be directly connected to the same switch. In contrast, iSCSI host bus adapters can be connected to storage routers located anywhere on the network. Cisco, for example, has already rolled out the SN4250 storage router.
Some panelists, though, expressed doubts over iSCSI's current advantages. At this point, network administrators can achieve the same "scalability" simply by plugging in more NAS (network-attached storage) boxes, maintained Camden Ford, senior product marketing manager for Brocade Communications Systems. Ford also insisted that most companies will continue to perform database replication over FC.
Brocade, a major player on the FC side, recently acquired iSCSI specialist Rhapsody. "We purchased Rhapsody to build more value into iSCSI," Ford explained. Specific objectives include storage virtualization tools.
Much like voice over IP (VoIP), iSCSI is "just waiting to be deployed," according to Ford. VoIP, though, has taken "a long process to develop," he illustrated.
InfiniBand, another new IP-based storage networking architecture, is meant to overcome the I/O bus bottleneck, raising throughout to multiple gigabytes per second by providing a point-to-point switched I/O fabric.
Current issues for InfiniBand include manageability, costs, and - most of all - availability. "A couple of years ago, InfiniBand was supposed to do everything for everybody," Hansen said. "That's probably a couple of years out."
At first, InfiniBand has been used mainly inside servers. Over the next year or two, however, the storage technology will be decoupled from servers. Initially, InfiniBand will be used to support clustered servers. After that, it will support direct attachments through cascaded switches, Deirling suggested.
Hansen said that CIM-based APIs will be used to manage InfiniBand as well as FC network storage architectures. "The level of InfiniBand management will be transparent (to administrators)."
Many management environments already support CIM, including HP OpenView, IBM Tivoli, and EMC's Prisa storage administration tool, according to Hansen.
Deirling pointed to further advantages from the future option of RDMA, an emerging standard for reducing latency on TCP/IP networks. RDMA is designed to let one computer copy data to the memory of another computer, with little involvement by CPUs.