Conclusion: Golden Times Ahead For ISCSI
The basic function of iSCSI, namely utilizing existing technologies to implement inexpensive SANs, works like a charm. In our tests, both the software-based iSCSI Server from DataCore and the hardware-based iSA 1500 Storage Array from Adaptec offered good performance paired with easy handling.
DataCore aims its SANMelody suite more at companies that wish to retrofit existing servers for iSCSI use, or that are looking to enter the iSCSI world for as little cost as possible. The price hierarchy of the various packages is organized by feature set, allowing even smaller companies to create flexible iSCSI storage solutions. A 21-day trial version lets you test out the software before you buy, and SANMelody Lite, which is an even more pared-down version costing only $199, makes the decision even easier.
Adaptec, on the other hand, chooses to go the hardware route - unsurprising, considering that this company supported and pushed the iSCSI technology from the beginning. The iSCSI-to-PCI-X adapter AHA-7211C serves to connect SANs or storage appliances to existing servers. To this end, the card sports a TCP/IP offload engine as well as an iSCSI offload engine. As a result, the system which houses this card has to deal with an even lower workload than if it used directly connected low-complexity storage solutions (DAS - Direct Attached Storage). While the 7211C isn't exactly cheap at $600, it is one of the few well-designed SCSI adapters available at the moment.
Finally, there is Adaptec's Storage Array iSA 1500 - a potent 1U server with a compact, task-oriented operating system and the ability to act as an iSCSI server in a SAN. Two Gigabit Ethernet ports ensure very fast network connections, while a third port is dedicated to configuration and administration. The server itself uses four 3.5" Serial ATA hard drives, which helps keep costs down - all of the bigger manufacturers now offer ATA drives that have been designed for constant operation in so-called near-line environments. Current drives offer capacities of up to 400 GB, allowing for a maximum nominal capacity of 1.6TeraByte in a 1U case. Costing several thousand dollars, such a Storage Module is obviously outside of the financial reach of Joe Average, but for mid-size companies, it is a safe investment. This is especially true given that the storage capacity can be increased quite easily as soon as larger drives become available.
