Published: 13 Mar 2008
| The marriage of virtualized servers and iSCSI SANs is turning out to be a happy one for many users. Since VMware announced support for iSCSI SANs in June 2006, virtualization users have embraced iSCSI's lower cost and reduced complexity.
Nearly two years later, the honeymoon still isn't over. Pat O'Day, chief technology officer at BlueLock, an Indianapolis-based provider of infrastructure as a service, says his young company has used only VMware and LeftHand Networks' iSCSI SANs in its two-year existence. "We were fully prepared that at some point we would have to investigate going into Fibre Channel [FC]," he says. "I still have it way out on the radar. But we're up to 50TB or 60TB now."
Cost and flexibility drove BlueLock's selection of iSCSI. O'Day calls iSCSI "a very loose technology. Fibre Channel is so physically dependent on the infrastructure." iSCSI makes it easy to boot servers from BlueLock's main facility to its Salt Lake City data center, he says.
iSCSI's lower cost was worth the slight performance difference. "Fibre Channel drives certainly are a little faster," says O'Day. "But they're not 300% faster."
Matt Simmons, network infrastructure manager at Golf Savings Bank in Mountlake Terrace, WA, also cites cost as his reason for choosing iSCSI over FC. The bank has been using VMware Infrastructure 3 in conjunction with EqualLogic iSCSI SANs for about two years. "You get so much more bang for your buck," he says.
Golf Savings did run into a performance bottleneck as the bank grew. "We had to step up to some beefier backplane switches to get the most performance out of them because we really hit them pretty hard," says Simmons.
iSCSI vendors EqualLogic (now part of Dell) and LeftHand have both seen an influx of customers since VMware's June 2006 decision. EqualLogic's product marketing manager, Timothy Sherbak, says that "definitely, enterprise customers have increased by virtue of virtualization."
Ben Bolles, director of product management at LeftHand Networks, says their adoption rates also went up after VMware's endorsement. "There's a certain majority of the customers that aren't going to deploy a particular technology until that vendor gets behind it," he says.
iSCSI is also making its way into virtualized server environments as a complement to FC. Bill Montgomery, manager of information systems at Lulu.com, says they use iSCSI for everything but back-end storage and e-commerce databases, which are handled by FC. "I think for general business computing, iSCSI is going to satisfy the performance requirements of 95% of your applications," he says.
Montgomery also likes iSCSI's simplicity. "Everything about Fibre Channel costs more, and it's not as easy either," he says. "A couple years ago it seemed like [iSCSI] had gotten to the point where it was mature enough technology to be able to rely on it."
Lulu.com encountered some issues with firmware versions between the iSCSI SAN and its HBAs, but "it was nothing that prevented us from implementing something that we wanted to do," notes Montgomery. He adds that the company's iSCSI HBAs, which are used to boot diskless blade servers, are the key to keeping processes simple and flexible.
Greg Schulz, senior analyst and founder of StorageIO Group, Stillwater, MN, sees the two technologies as intertwined. "You could make the claim that virtualization is the key to iSCSI or [that] iSCSI is the key to virtualization," he says. Schulz predicts an upward trend in iSCSI adoption as IP comfort levels shift. There's still baggage, he says, "but barriers are dropping faster."
Golf Savings Bank's Simmons isn't looking back. "I have not heard a compelling reason why I need Fibre Channel," he says, "other than you need to spend more money."