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General Information
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July 6, 2007
• Vol.29 Issue 27
Page(s) 23 in print issue
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SAN & Enterprise iSCSI Storage
Enhance Technology’s Solution For The Rensselaer Polytechnic Institute
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 When IT and data center managers make purchasing decisions without fully researching a product (that is, based on marketing gab only), they run the risk of getting into a technology that doesn’t fit their specific data center requirements (and sometimes their budget). But if the homework is done properly, life is smooth.
After careful research and product review, there came a point in the purchasing decision where reliability settled the score for A.J. Lacomba. The cost of the perfect storage solution for the Rensselaer Polytechnic Institute in Troy, N.Y., came into play, but the flexibility, redundancy, and Linux support sealed the deal. Goodbye RAID 5, hello RAID 6. It was iSCSI storage to the rescue. Lacomba, manager of information systems for electrical, computer, and systems engineering at Rensselaer, spoke to us about his decision to buy SAN and Enterprise iSCSI storage-related products from Enhance Technology.
 The Problem
Lacomba describes the problem Rensselaer was trying to solve when it decided to purchase Enhance Technology’s IP San 1U 4-Drive, 2U 8-Drive, and 3U 16-Drive Rackmounts. He comments, “What are the two absolutely worst things you can tell a user? First is that you lost their data, and second is that the system is down. RAID 5 mitigates disk failure; however, it does nothing if the entire RAID goes down. Computer room failures are not that rare—water pipes can rust, leak, and flood a room, and HVAC and power systems can overload or fail.” Lacomba says with these things in mind, he decided to design and build a highly redundant, fault-tolerant, data storage solution with remote mirroring (all with only a relatively small budget).
Lacomba says his main servers all had RAID 5 DAS (direct attached storage), and although they have been very reliable, they have limited flexibility and redundancy. He also had offline backup servers that he could easily bring online (in case of server failure); however, this required human intervention. “About a year ago,” he says, “I fired up Google and started researching possible SAN solutions. All the big players had advanced fiber solutions along with advanced pricing. So I continued to look at other solutions and finally settled on using iSCSI. We wanted something fairly mature and reasonably supported under Linux.”
The iSCSI architecture gave Rensselaer the flexibility it needed, in an environment it was already familiar with (Ethernet), and came at a reasonable price as well. Lacomba says iSCSI would allow him to disconnect the storage and the processor sections of Rensselaer’s servers. He notes, “Now we could direct any storage resource to any compute processor without any physical intervention. In addition, iSCSI gives us the ability to run a distributed file system, thus allowing us to run multiple file and Web servers all serving the same data at the same time.”
This combination of SAN and compute servers offered Lacomba a highly redundant fault-tolerant system. He notes, “We were also able to provide mirrored remote replication by connecting the remote switches using trunked fiber lines.”
The Design
With this all in mind, Lacomba designed Rensselaer’s current SAN (two server rooms, each including three servers, two 2GB Ethernet switches, and two iSCSI arrays). In this SAN, the servers are connected to the iSCSI switches using iSCSI TOE (TCP Offload Engine) cards. Each array is mirrored at the server level, creating two fully independent paths. One array is located locally in the server room and the other array in another server room on the other side of the building, several floors away. Lacomba says this remote mirroring provides a safety net (in case of catastrophic room failure) with absolutely no loss of data.
"In addition," he says, "we also mirrored the servers between the rooms, minimizing any downtime should a server room failure occur. The data itself is backed up using snapshot on remote servers using the same iSCSI arrays. Since the arrays are identical, they also serve as backup units to the main SAN arrays.” Lacomba says this solution also allows Rensselaer to easily add additional servers and arrays.
Lacomba says he did consider other products in his quest for the best solution. He comments, “Initially we considered SCSI DAS units, Fiber Channel SANs, NAS solutions, and competing iSCSI vendors.” Lacomba says he considered making his own iSCSI arrays but decided it would be best to get a prebuilt, optimized, and supported solution from Enhanced Technology.
The Decision
So why did Rensselaer choose Enhance Technology products? “At the time we were putting together the hardware,” Lacomba notes, “there was a limited selection of storage devices with hardware RAID 6, built-in alert and reporting functions (including SNMP and email), auto shutdown (initiated by UPS units), redundant and trunkable data connections, and support for large packet sizes, all managed by an easy-to-use Web interface.” He says Enhance Technology’s products had the features he was looking for at a low entry cost.
As with all new technologies, Lacomba says Rensselaer had some early adopter issues. He explains, “Initially we had some problems with configuring the RS8 IP units; however, after contacting Enhance Technology support, we were given a BIOS update that fixed the problems we were experiencing. We also had some issues with quality control that have since been resolved. Since the solution worked so well, we purchased additional arrays and have had no problems whatsoever. When we did have problems initially, Enhance Technology was responsive and quick to provide support and solutions.”
Overall, Lacomba says he is happy with Enhance Technology’s products and the support that they have provided. He says there were initial concerns regarding latency issues; however, his tests indicated that the Enhance Technology RAID 6 units were roughly 20% faster than the built-in RAID 5 arrays using SCSI drives on his servers. Rensselaer’s SAN configuration, using mirrors and remote replication, provides access times that are comparable or slightly faster.
Has Lacomba’s department had any regrets? Lacomba answers, “No. We have been very happy with our SAN design and choice of hardware vendors. The Enhance Technology products have been working flawlessly.”
Did the product solve the company’s problem? Lacomba concludes, “Yes. For an organization that is our size (including our budget), the SAN we built using Enhance Technology’s storage arrays has given us a new level of redundancy, flexibility, and performance at a very competitive price.” 
by Chris A. MacKinnon
ULTRASTOR RS8 IP
An intelligent network iSCSI RAID System, hosting a built-in 64-bit RAID controller and 3Gbps SATA disks. The ULTRASTOR RS8 IP is designed for high-impact and high-volume network storage environments.
“Our main servers all had RAID 5 DAS (direct attached storage), and although they had been very reliable, they had limited flexibility and redundancy,” says A.J. Lacomba of Rensselaer Polytechnic Institute.
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