iSCSI: Too Little, Too Late

Such was the case with iSCSI, an elegant storage concept that operates over 1 Gbps Ethernet (GbE) and has been well-implemented. However, the limits of GbE may force this protocol into the back seat as older Fibre Channel technologies steal the hearts of SMB IT managers with lots of bytes to move and little time to move them. Vendors of major disk storage and backup systems tell me that partners who support the SMB market are demanding Fibre. And vendors are complying at near-breakneck speeds.

My love affair with iSCSI began the first time I used it with an Overland Storage REO R2000 2-TB disk-to-disk-to-tape (D2D2T) backup system. These high-end units are designed to accept simultaneous backups from multiple servers at high speeds. The R2000 came from the manufacturer with iSCSI support built in. My simple task was to install iSCSI client drivers on five high-end Microsoft Windows servers.

With the drivers in place, disk drives on the D2D2T device looked to the servers like locally attached SCSI drives. In a few pain-free minutes, I had created a backup SAN. Running my favorite backup software, Backup Exec, on each of the servers, I was able to push enough bytes at the D2D2T unit to keep it very busy. All five of the servers were backed up in little more than the time it usually takes to back up one, and the data was poised to be archived to tape at a more leisurely pace.

Still, iSCSI is not Fibre; in fact, it operates at half the bandwidth of modern Fibre-based technologies. It also suffers from limited operating-system support. To date, there are iSCSI client drivers for Windows and Linux. SCSI over Fibre Channel Protocol (SCSI-FCP), originally a 1-Gbps technology, now runs at 2 Gbps. And you can buy SCSI-FCP 2-Gbps hardware that works with a wide range of operating systems from the likes of Adaptec, Cisco, HP, IBM and QLogic.

Like iSCSI, SCSI-FCP provides client servers with the same local view of external devices, be they disk or tape units. You configure SCSI-FCP as you would a switched Ethernet network, using SAN switches and Fibre adapters. Quality SMB-level SAN switches cost less than $900 per port, and adapters cost roughly $1,000 each. That doesn't compare too well with GbE at less than $100 per quality GbE port and $120 per quality GbE adapter, but I expect Fibre switch and adapter prices to come down--and there is that extra gigabit of throughput.

Race To Embrace SCSI-FCP
Almost as soon as that Overland Storage REO R2000 I had mentioned arrived at my test lab, the folks at Overland wanted to arrange a teleconference. I was so busy trying to assimilate the wondrous new technology they sent me that I kept putting them off. Finally, in late April we had that teleconference. That's when they told me about their newest product, the R4000. The R2000 supports only iSCSI. The R4000 supports both iSCSI and SCSI-FCP and boasts a number of other partner-driven improvements over the R2000, released only seven months earlier in September.

How much does SCSI-FCP add to the cost of the R4000? With iSCSI alone, the 2-TB R4000 without the D2T side of D2D2T has an MSRP of $13,500. You can add SCSI-FCP for another $4,000. That, my friends, is a pretty good deal. At the moment, I'm sold on SCSI-FCP for my customers who need the bandwidth. I just wish 10-Gbps Ethernet wasn't peeking over that horizon.

Barry Gerber ([email protected]) is a Los Angeles-based networking and storage consultant.