InformationWeek
Defining The Business Value Of Technology
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October 2, 2000 |
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Storage Area Networks
Everything In Its Own Place
continued...page 4 of 4
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Overall, Interphase was able to demonstrate a complete product and was the only vendor to bring a diverse, multivendor product likely to be representative of what businesses deploy in the real world. We're particularly impressed with Interphase's interoperability and its dual Fibre Chan-nel/Gigabit Ethernet card, which could lead to a fully redundant SAN/Ether-net product using low-profile servers. With better integrated management and with automatic failover within or between Fibre Channel networks, Interphase's offering would be a tough product to beat.
QLogic entered a minimal configuration in our tests. Its system consisted of two servers on the SAN, a single switch, and a single storage device. Best known as a host bus adapter and chipset manufacturer for both PCI-to-SCSI and PCI-to-Fibre Channel, QLogic had some difficulty obtaining additional hardware for the tests, and was plagued by inexplicable difficulties with the Fibre Channel switch it brought for the test. The consensus was that the switch was damaged in shipping. Because of the limited hardware, QLogic wasn't able to perform many of the SAN tests that we had requested in the review plan. Even so, QLogic was able to construct and demonstrate a small working SAN product with solid failover functionality.
QLogic's SAN product uses two servers with QLA2200F/66 host bus adapters. The QLA2200F series is an optical card containing a 1-Gbyte per second Fibre Channel connection capable of full-duplex (200-Mbytes per second) data transfers. The "66" designation specifies that the card requires a 64-bit 66-MHz PCI slot. The servers were a four-Pentium III Xeon-based Compaq ProLiant DL580 running Windows NT Server and an HP LH-6000 six-way Pentium III Xeon also running Windows NT Server.
QLogic used a third server, a two-way Pentium III-based Compaq ProLiant DL380 running Windows 2000, as a management console. It connected to the other servers via Fast Ethernet and didn't have a host bus adapter.
Ancor provided the Fibre Channel fabric switch for the test. Ancor's SANBox 16HA (high availability) switch has 16 full-duplex Fibre Channel ports and can be equipped with dual non-hot-swappable power supplies, though the switch used for this test had only a single power supply.
The sole storage device is one of Sun's new StorEdge T3 Fibre Channel RAID disk arrays, which contains nine 18-Gbyte FC-AL drives; this product was the only one in our lab test to use Fibre Channel drives, rather than SCSI drives. The StorEdge was partitioned into four LUNs for the test, two for each server.
During the test, both servers read streaming video from one LUN, while copying data back and forth between the other two LUNs. The Fibre Channel drives and RAID controller contribute to Sun's relatively high price of $32,500 for the storage box alone.
QLogic chose to demonstrate a SAN with redundant paths that had two host bus adapters in each server, each connected to separate switch ports. There was only one Fibre Channel connection from the Ancor switch to the StorEdge array.
The biggest difficulty with the QLogic test appeared to be faulty switch hardware, and those problems limited the amount of time we had for testing. The test was also limited in that QLogic only brought a single storage device and no backup device, and chose to use only Windows NT servers, so we were unable to view cross-platform compatibility and a live data backup/restore operation.
Despite those limitations, QLogic demonstrated a working SAN that ran on Windows NT and was capable of handling simultaneous data transfers. We're impressed by its automatic failover of the redundant fiber links to redundant paths, as configured in its QLconfig management software.
With dual host bus adapters in each server running to the switch, the system recovers from a hardware failure (simulated by unplugging a GBIC from the switch) in less than five seconds. In another case, we used the QLview management tool to disable a server's active host bus adapter, the server hung on for about three minutes before recovering and switching to the redundant host bus adapter and path.
Our biggest complaint is the lack of management. The QLogic host bus adapters come with two tools, which can run on Linux, NetWare, and Windows: QLview for Fibre, which provides admin capabilities for host bus adapters and logs events to the NT Event Log; and QLconfig, which administers LUNs and failover paths.
Both tools work on local host bus adapters, as well as on host bus adapters in network-accessible servers using Ethernet or IP-over-Fibre Channel. Neither presents a complete product. When we failed one of the servers' redundant links, for example, the only possible notification was a blinking toolbar icon on the management console--there are no E-mail, SNMP alerts, or other notification.
When we pulled up QLconfig and checked a path view, it showed us that a failover had taken place, but not where. To learn why, we had to fire up QLview, check the appropriate server, and drill down to the host bus adapter. All we saw was that traffic wasn't flowing--not a true management product for a production SAN.
The Ancor SANbox includes an embedded Web server that downloads a Java applet called SAN Surfer to a management station; the applet runs under Windows (we used it on a notebook) and on Linux, though Solaris is promised for the future. It, too, is a configuration tool, not a management product. Although it shows the switch's current configuration, there's no alert and no active monitoring of the SANBox's SNMP traps. To tell if a port goes down, you'd have to be actively managing that switch to visually detect that a state has changed.
The Sun StorEdge array has its own management utility, called StorEdge Component Manager, which isn't integrated into the rest of the product.
Overall, we're impressed with the configurability and reliability capabilities of the QLogic/Ancor product. We can't attest to its backup, scalability, or cross-platform abilities, and the management is weak, so we can't give QLogic top marks, but there's no doubt that QLogic has the connectivity issue covered.
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