Feature: What can iSCSI do for you?

We know what iSCSI is - a protocol that defines how devices move block-level storage data over IP links.

We recognize the potential benefit - an opportunity to extend access to storage over existing Ethernet networks.

We know it has big-time backers - Adaptec Inc., Alacritech Inc., Cisco Systems Inc., Emulex Corp., Hewlett-Packard Co., IBM Corp., Intel Corp., Microsoft Corp., Nishan Systems Inc. and Network Appliance Inc., to name some.

But what can iSCSI do for you?

How about letting you go and buy three USB floppy disk drives, hang them off a Linux server and configure them into a RAID array from a Windows 2000 Server over a wireless network?

Of course, no one would build a RAID array with 1.44M byte floppy disks, but the iLabs team exercise showed that many things are possible with iSCSI. "It does go to demonstrate that iSCSI gives you the flexibility to build any real- life storage application you need and then run it over IP," says Allen Gwinn, iLabs IP Storage Initiative team lead and senior director of technology at the Cox School of Business at Southern Methodist University in Dallas.

The iLabs team then backed up a local disk drive on a Win 2000 Server equipped with an iSCSI-supported Alacritech network interface card to another drive located on a "just a bunch of disks" box across a Gigabit Ethernet link. No surprises here. It works.

Next, the team tested how iSCSI can be used to remotely boot a computer without any hard drive or directly attached disks. In this scenario, a Win 2000 box with no hard drive hit a Cisco Catalyst 4000 switch and, via a Dynamic Host Configuration Protocol (DHCP) server software attached to that switch, picked up a standard IP address. Also residing on the DHCP server is Cisco's iSCSI Network Boot software that points the Windows machine to a drive hanging off an iSCSI storage target on the network to remotely boot it. This type of remote booting capability has been available in the Fibre Channel realm for some time.

While the iLabs team only demonstrated that this remote boot application would work with a single server, the technology could be used to let a large number of servers, such as blade servers in a rack-mounted chassis, boot up from a single storage system.

"Think of the administrative implications of that," says Mike Frase, an iLabs engineer and a Cisco technical support engineer. "Any time you need to change security parameters or modify applications, you just make those changes once and they get populated to your remote servers when they boot up."

The iLabs storage team also tested how iSCSI can help deliver video on demand across IP networks. The team stored video clips on an IBM Total Storage FAStT500 Fibre Channel storage device attached to a Cisco MDS 9216 multilayer fabric storage switch that sports Fibre Channel and iSCSI interfaces. On the other side of the IP cloud sits a video server and a client PC. The client machine requests a video feed from the server, which downloads the stored clips using iSCSI over the Gigabit Ethernet network.

On that same test bed, the team demonstrated how iSCSI could help deliver a video surveillance application. A digital camera feed sent images through the IP network to a desktop where you could view the images live and to the IBM storage device, where they could be saved to disk. The surveillance video then is made available to a second PC with a 10-minute delay. By saving these images to disk and then using iSCSI to deliver them back over the IP network, the viewer gets easy, precise access to the video without weeding through piles of video tapes.

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