Exclusive: Intransa realizes dreams of 10Gb iSCSI

Ever since the announcement of 10Gb Ethernet, many storage managers have looked forward to 10Gb iSCSI. The hope was that for the first time, iSCSI would actually have not only a cost advantage over FC (Fibre Channel), but a performance advantage as well.

Intransa'sStorStac PCU100 is one of the first 10Gb iSCSI systems available. It won't be formally released until later this month, but InfoWorld was given an exclusive opportunity to review it. Based on my testing, I can say that storage managers will be pleased to know that their hopes for 10Gb iSCSI have been realized.

Intransa'ssystem boasts some unique features, different from most iSCSI systems, such as its basic architecture. Unlike other iSCSI and FC storage systems, the StorStac connects all drives via Ethernet. Each drive has its own IP address and every two drives share a GigE (Gigabit Ethernet) connection, providing each drive with more bandwidth than it needs.

High-speed storage

My test system had two storage controllers and two servers, connected to a 10GigE switch, and four storage units connected to 2GigE switches with 10GigE uplink ports. The storage controllers were connected to the switches via the uplink ports. The two servers ran Windows 2003 and RedHat Enterprise Linux 4.0 and were equipped with Neterion 10Gb Ethernet NICs.

The PCU100's performance is all that one might hope for. In testing, I saw sustained throughputs of 700Mbps (5.6Gbps), which is better than 4Gb FC performance. With two controllers, I saw throughputs in the range of 830Mbps to 900Mbps.

IOPS will not be as high with iSCSI as with high-performance FC arrays, due in part to the differences in latency between the two technologies. However, according to Intransa, targeted applications for its product typically use streaming content, such as video processing, video on demand, medical imaging, video surveillance, and disk-to-disk backup and recovery, where IOPS performance is less relevant.

Intransauses the same drives and enclosures for all three of its systems, which run at 1Gbps, 2Gbps, and 10Gbps. The differences between the three are in the head units rather than in the drive subsystems. This approach ensures that your investment in storage is largely retained should you upgrade from the lower speeds to 10Gb.

Superior scaling

The StorStac system offers excellent scalability, not only in allowing existing users to easily and simply upgrade to a higher-speed system, but also in allowing for as many as four storage controllers and 15 storage shelves. You can even add iSCSI storage from other vendors to the PCU.

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The four controllers are configured as a cluster. Bringing an additional controller online is pretty straightforward: The system's cluster management software will detect it once you configure the IP address, and it will ask if you want to add the new controller to the cluster. Adding additional disk shelves is just as easy: Connect Ethernet and power cables, power on, and the controller auto-discovers the drive shelf. In about two minutes, the additional drives are available.