Fibre Channel was definitely not top of mind when Chris Brown hit the wall on disk space and, in mid-2005, decided to go shopping for a SAN. Brown is IT manager for DeltaValve, a division of Curtiss-Wright Flow Control. "I have an IT staff of two," he explains, "and we do not have the resources to support Fibre Channel."
Instead, Brown opted for the convenience and low cost of an IP-based network storage system. To that end, he bought five NSM 150s from LeftHand Networks as building blocks for a new iSCSI SAN. Each unit comes with four 250GB drives, so he had a cluster of five terabytes of new storage that, unlike a Fibre Channel SAN, would require little in the way of specialized skills to maintain.
The value proposition of iSCSI storage has always been its simplicity and low cost compared to Fibre Channel. All you need is capacity on a Gigabit Ethernet network -- no special training in an esoteric protocol, just a little education on top of basic networking skills. An iSCSI SAN can also smooth the path to data replication and disaster recovery, especially over long distances. And if speed is an issue, 10GbE (10 Gigabit Ethernet) is already here, if somewhat pricey.
Drue Reeves, research director with the Burton Group, calls the iSCSI SANs from such vendors as LeftHand, DataCore, and FalconStor "software-only targets. They are relatively cheap," he explains, "because they run on standard hardware. They are powerful because you can cluster them and add storage virtualization on top, so a LUN [logical unit number] can fail over to another target, and the user never knows."
It was clear that iSCSI had arrived when Microsoft put an initiator in Windows Server 2003. What was not so clear was where iSCSI would go. Fibre Channel still rules the SAN market, and Microsoft didn't follow suit with an iSCSI target until last year.
But last fall iSCSI got a huge boost when VMware, the hottest name in virtualization, added iSCSI support. To get the most out of virtualization, you need a SAN -- and now you can do it without Fibre Channel.
The virtualization connection
DeltaValve's Brown, who isn't afraid of getting under the hood, quickly saw the potential of his new SAN. "I moved everything -- SQL Server, Navision, SharePoint, Exchange Server, and an Oracle database that runs our PLM (Product Lifecycle Management) System -- onto them," he says.
Brown's willingness to tinker also took him deep into the world of virtualization. "About three months after we got the SAN running, I brought VMware into the mix. Virtual storage from the SAN and server virtualization from VMware go hand in hand."
Brown has two host VMware servers (both homegrown, Quad AMD Opteron-powered boxes) and runs eight virtual servers on each. "The beauty," he says, "is that if one host goes down, we can use the other host to mount the same volume and be up in a matter of minutes."
Thane Morgan, director of information technology for the town of Fishers, a suburb of Indianapolis, had virtualization on his mind from the start. He also looked at LeftHand but did not like the way that software vendor made the hardware decision for you. "Being dependent on their [LeftHand's] control of hardware drives my cost up," he says.
So Morgan bought SANMelody software from DataCore that is hardware-agnostic. "For about US$60,000, I got two brand-new, dual-core Dell 1950s to be my new app servers. Then I was able to load SANMelody onto the best two of my old servers to create my SAN."
Hanging SATA drive cages off the converted SAN boxes gave him six terabytes of storage. "I am licensed for 16 terabytes with DataCore," Morgan says. "With LeftHand, for the same amount of money, I would have been stuck at two four-terabyte nodes without my new app server boxes."
He bought the hardware and software and did prototyping last summer, so when VMware announced support for iSCSI in September, he was ready. "We got it all running in December, and, finally, my server is completely decoupled from the hardware."
Clearly, Morgan is excited by the power of combining server virtualization with SAN technology. "If I had virtual servers and no SAN, it would be easy to back up and restore the server on another machine if, for example, I needed to do maintenance. But this still takes time and probably means taking some applications offline. When you add the SAN, you can do the same thing with no interruption of service."
Consultants such as Jamie Anderson, president of Emergent Networks, a consultancy and VAR in Minneapolis, are finding the combination of iSCSI and virtualization is enough to convince hesitant clients to make the leap to shared storage.
Anderson cites a recent engagement with a small bank. "This is a new bank in Savage, Minn.," he says. "Without iSCSI they would not have considered a SAN. But we just put in an EMC Clariion and two virtual servers. Right now they only have 800GB of data, but they are in good shape to grow, and there was almost no learning curve since it is all Ethernet based."
Anderson adds that virtualization was one of the drivers behind Chief Manufacturing's selection of an iSCSI SAN. "We did this about 18 months ago," he says. "We use iSCSI to mount local drives to Exchange and SQL Server."