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.
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.
