This article can also be found in the Premium Editorial Download "Storage magazine: iSCSI: Ready for prime time?."
Download it now to read this article plus other related content.
But other users have overwhelmingly adopted the use of software initiators from Cisco Systems Inc., Microsoft and the open-source community because they're inexpensive or freely downloadable from a vendor's site.
"We use the Microsoft software initiator and it works fine," says Mark Kash, IT specialist for the U.S. Army Corps of Engineers in Huntington, WV. "It's reliable and I haven't had any instances where it's corrupted anything," he says. "Originally, we considered using TOE cards from QLogic because we were thinking a firmware-based platform may be more reliable, but we saved money using the software-based alternative."
Microsoft's iSCSI Software Initiator Version 2.06 is the most popular iSCSI initiator. It supports multipathing for load balancing and failover, 64-bit platforms and IPv6. Multipathing lets the initiator establish multiple sessions with one target, enabling load balancing and failover among multiple network adapters or HBAs.
"We ran some performance tests to see the difference between iSCSI and Fibre Channel, and we saw what the industry saw: iSCSI is able to offer about 80% the performance of 2Gb Fibre Channel," says UniSource Energy's Rima. "4Gig Fibre Channel is a little bit more, but it's
| not substantial enough given the cost to use it."
Rima chose iSCSI because it fulfilled his "performance needs." He runs Microsoft Exchange on iSCSI, and has been able to scale his storage up but "maintain a network topology that's low cost and low impact in terms of support."
Jim Bollinger, systems and network engineer at Washington and Lee University in Lexington, VA, has seen the same performance results as Rima. Bollinger installed Overland Storage REO disk-based appliances to back up his storage environment.
"iSCSI has been capable of doing everything we need it to do," says Bollinger. "You could take iometer.exe and take the array right up to 100Mb/sec. It's every bit as good as local SCSI and sometimes better. We've had no trouble on big files filling the pipe on our LTO-3 backup--up around 70MB/sec to 80MB/sec--and we've been backing up 7TB to 8TB a day."
This was first published in April 2008