Whether it's Fibre Channel or iSCSI, small and medium-sized businesses are realizing that SANs make more sense than direct-attached storage.
By Alan R. Earls
It used to be that SANs were essentially a large enterprise story. Fortune 500 companies demanded rock-solid storage infrastructures and a coterie of pricey vendors delivered.
But the worm has turned and small to medium-sized businesses (SMBs) are now getting into the driver's seat, and SAN vendors are reacting with highly functional, relatively inexpensive SANs—both Fibre Channel and iSCSI.
Steve Duplessie, founder and senior analyst at the Enterprise Strategy Group consulting firm, says that the storage pains at small businesses are the same as at large enterprises. "They're all experiencing massive, chaotic growing pains," says Duplessie. However, unlike conservative large companies, smaller companies "are probably more willing to take leaps of faith. When you only have a few IT people you're open to something new if it can help you stay competitive," he says.
But the story isn't just about large vendors faced with a maturing enterprise market and changing their ways to chase a new class of customers. It is also a case of feisty start-ups challenging the status quo with a mix of price and performance that appeals not only to SMBs but also to more savvy and demanding enterprise customers.
Duplessie notes that a number of iSCSI start-ups are providing "idiot-proof" IP SANs at affordable prices. "Cost and complexity are getting thrown out the window, which is why we're bullish on iSCSI," says Duplessie.
Bullish in Texas
Underscoring the point about storage pains being universal, a small Texas-based university recently found relief with an inexpensive SAN. "We migrated from direct-attached storage [DAS] because we were always running out of disk space," explains Robert Forkner, a systems engineer at Abilene Christian University (ACU). "We also wanted something that would scale with our demands rather than having to purchase single solutions for each issue that arose."
ACU purchased its first SAN three years ago, with help from Zzyzx Peripherals, a San Diego-based storage integrator specializing in RAID and tape solutions. At first, Forkner considered NAS because it was simple and provided plenty of capacity without overhead, but the university ultimately decided to purchase a SAN because of its scalability.
"We have several servers on campus that provide services to the faculty and student body that must have large disk capacity available to them," says Forkner. "Our disk utilization is mostly comprised of very small files. As a result, it was not unusual for a full backup to take 24 hours to complete."
Forkner reports that his SAN implementations have been completely problem-free. However, he admits, "SANs can become very complicated. If you don't have experience, be sure that you can get the proper support from the vendor."
In ACU's case, Forkner says it was helpful to have staff experience in Veritas Volume Manager, "especially when you want to add redundancy with multiple HBAs and create multi-pathing." No one should treat a SAN like it's just a glorified JBOD. SANs require expertise to implement and manage successfully." ACU is currently in the process of adding another terabyte to its SAN infrastructure to meet growing storage requirements and new IT initiatives.
CNS is a 58-person company in Minneapolis that designs and markets consumer healthcare products such as the Breathe Right brands. The company's data mainly consists of sales, finance, and inventory information in Exchange and SQL Server databases. CNS recently needed to upgrade its servers and operating systems and wanted to make sure the company had flexible storage capabilities well into the future.
Don Himsl, CNS's IT director, says the company began to consider a SAN when it recognized that existing servers were quickly approaching obsolescence and would need to be replaced along with their attached storage. "In our DAS environment it became difficult to estimate storage capacity," Himsl explains. "Although we wanted to be able to estimate storage needs and assign capacity to the servers that needed it, we found we couldn't because historical data just wasn't a useful guide."
Like others in this situation, Himsl was overbuying storage when he purchased servers. But the servers would eventually run out of storage. "Tasks like implementing RAID 5, which would require re-striping, could keep a server down for days," he says.
Rather than continue that pattern, Himsl first bought diskless servers, which reduced costs. After that, we started looking at storage virtualization, dynamic capacity, and snapshots. "We initially considered an iSCSI SAN, but we didn't want everything in our storage center to be dependent on a new technology," Himsl explains. So the focus shifted to Fibre Channel. Working with The Davenport Group, an integrator in St. Paul, CNS installed its first SAN about a year ago. "It seemed to fit our needs and it was just a two-day installation," he says.
But within a short time, Himsl found he wasn't satisfied with the system's virtualization capabilities. "We wanted to be able to plan and aggregate and then apply storage to different servers, but it was difficult," he explains. The Davenport Group recommended Storage Center, from start-up Compellent. Storage Center is an integrated, modular SAN solution that automates functions such as allocation, capacity utilization, and data recovery. "We installed it in about two hours and then we had both SANs running on the same Fibre Channel fabric so we had to migrate the data," says Himsl. "The only real challenge was imaging the boot sector and moving that across." Now, almost the entire Microsoft-based shop, with 10 diskless servers, runs off Compellent storage shared via a SAN.
Himsl says that the migration from DAS has made capacity planning much simpler. "Our administration time is down substantially—probably by 70%. And we've doubled capacity from 1 to 2TB but utilization is up." A handful of servers remain unconnected to the SAN, "but almost all our critical data is now on the SAN," he adds.
CNS's first round of SAN shopping focused on large vendors such as EMC and Dell, but CNS couldn't find the features and functionality it needed at an acceptable price point, and those vendors' solutions seemed complicated relative to Compellent's wizard-driven technology, according to Himsl.
Himsl now counts himself as a Fibre Channel convert: "Throughput is fantastic and the administrative load is lower than we anticipated."
Centralize and simplify
Tired of constant storage emergencies, Carla Hedding, the system administrator at Wolf Etter, a 90-person accounting firm in Mankato, MN, also migrated to a SAN. In addition to requiring storage capacity for its internal programs, research, and billing records, Wolf Etter's disk arrays store years of critical financial data—including tax returns and accounting records—for more than 5,000 clients. About a year ago, the company had six servers and two satellite offices.
"We were constantly expanding each server to maximum storage capacity, but we were always running out of space or the space wasn't where it was needed," recalls Hedding. "I'm a one-person show and managing disk space was taking an awful lot of my time." Furthermore, it was costly to add capacity to the company's previous DAS configuration. A third-party consulting firm—Clearnorth—recommended a SAN based on Compellent hardware and software. Hedding particularly likes the way the Compellent system permits mixing drives from different manufacturers and with different speeds.
Hedding estimates that the Compellent solution was about two-thirds the cost of some other SAN solutions that Wolf Etter considered. With the help of Clearnorth, Hedding says implementation was quick, despite the fact that the company added two new servers and upgraded other equipment and operating systems at the same time.
Hedding also reports that storage monitoring is easy and intuitive with the Compellent SAN. "We had a situation where we underestimated our storage needs so everything came to a screeching halt, but we used the snapshot feature and recovered fully within a few hours—far faster than with our older tape-based recovery process," says Hedding.
Richard Kruszewski is a network administrator that serves the needs of about 500 users at the TBWA\Chiat\Day ad agency in Los Angeles. "We're open 24 hours a day and have people coming to work at all hours, which means we must have high availability," says Kruszewski.
TBWA\Chiat\Day originally used DAS, which led to multiple islands of storage that could not be centrally managed or provisioned. Available capacity could not be properly allocated, leading to wasted capacity for some users and shortages for others.
To solve some of those problems the ad agency deployed an SCE 510 Cluster and low-cost Serial ATA (SATA) RAID technology from start-up Candera for its primary storage. The solution enabled the agency to successfully move from DAS to a Fibre Channel SAN. TBWA\Chiat\Day combined the SCE 510 Cluster with SAN switches from QLogic and two Apple Xserve ATA RAID arrays—a cost-effective solution for expanding and allocating storage without sacrificing performance or reliability, according to Kruszewski. The SAN has about 8TB of raw storage that is accessed by approximately 500 users.
The Candera SCE 510 network storage controller creates multiple tiers of storage. This simplifies management, lowers costs, and improves service levels, according to Kruszewski. The SCE 510 Cluster features active-active fail-over for high availability and continuous access to data. The cluster also provides error tracing and error handling in high-load environments, and SAN interoperability through intelligent object-based device characterization.
TBWA\Chiat\Day also purchased a Candera SCE 510 Cluster for its New York office. That system will be used to aggregate seven Apple Xserve RAID arrays with 21TB of capacity.
Kruszewski wanted a centralized and scalable solution to deal with frequent user demands for instant storage increases. The company considered SAN solutions from larger vendors such as EMC, LSI, and StorageTek, "but even a couple of terabytes was prohibitively expensive," says Kruszewski. He went with Candera's solution in part for cost reasons and also because the system works with Apple Xserve systems.
He also likes Candera's support for inexpensive SATA drives. "We don't have to put all our data on expensive Fibre Channel disks," says Kruszewski. He says the results were that the company was able to get two times the storage for half the price.
Kruszewski admits there were some hitches when the company first implemented the SAN, much of it due to his inexperience with Fibre Channel SANs, but in the end the company didn't need to hire any additional staff.
"Definitely plan for redundancy and make sure there are no paths of failure in the SAN," Kruszewski advises. "That's what I did wrong in the beginning." He also notes that SATA may not be as robust as Fibre Channel disks, "but I did RAID 5 and mirroring so if I lose a disk, users won't notice."
For Stephen Greenlee, the IT director at Escondido, CA-based Tri-Ad, an 80-person employee benefits consulting and administration services firm, the decision to move to a SAN was driven by the nature of the company's business, which includes managing retirement accounts, COBRA spending, and flexible benefit spending accounts for clients.
"Our server hardware and direct-attached storage was outdated and we had very high capacity demands, which is why we initially looked for a SAN solution," says Greenlee.
Tri-Ad receives an average of about 10,000 electronic faxes each month in connection with the flexible spending accounts it manages. "Since we plan to double that part of the business over the next couple of years we'll double our storage requirements—and that's just one example," says Greenlee.
In addition, Tri-Ad's traditional backup process took up to eight hours a night—another reason that the company opted for a SAN with snapshot capabilities.
"I was very interested in an iSCSI SAN, because of the low cost compared to Fibre Channel," says Greenlee. He also considered NAS, but went with a SAN because he needed block-level storage.
Tri-Ad's SAN is based on hardware and software from EqualLogic, an iSCSI start-up. "Setup was a snap, and almost all the functions we need are built in," says Greenlee.
Tri-Ad started with a terabyte of storage in its Oracle, SQL Server, and Lotus Domino environment. The iSCSI SAN provides two scheduled snapshots a day. "It has volume copy so I can instantly clone a volume online: It just takes a second," says Greenlee. He plans to acquire another iSCSI subsystem for a remote site so that the company can do synchronous replication.
Alan R. Earls is a freelance writer in Franklin, MA.
iSCSI enables consolidation and virtualization
By Eric R. Schott
Managing storage and reducing administration costs are at the center of an increasingly complex IT problem that challenges both small and large organizations. Today, the majority of businesses still have storage that is directly attached to servers, which becomes expensive, difficult to grow, and limited in management capabilities, especially as servers proliferate.
SANs provide a solution to many storage management challenges via the ability to consolidate storage for many servers in a centrally managed resource. However, until recently Fibre Channel was the only means of implementing a SAN. While justifiable for large enterprises, Fibre Channel SANs come with significant initial and ongoing costs as well as administration and management complexities that many organizations cannot justify. The arrival of Ethernet-based SANs and the iSCSI standard presents another option for SANs, making the benefits of consolidated storage available to nearly all businesses.
By combining the simplicity of Ethernet networks with advanced storage features, iSCSI SANs can deliver simplified storage management and consolidation at a reasonable price. As the iSCSI market expands, IT managers are tasked with understanding the technology, potential benefits, and how to achieve a lower total cost of ownership (TCO) for their storage solution.
Controlling costs and improving storage management can be achieved with a SAN that couples consolidation and virtualization with IP connectivity. Storage consolidation expands device connectivity and reduces points of management, while virtualization delivers a centralized, flexible method of management that masks the complexity of storage infrastructures and reduces administrative overhead.
How iSCSI works
Using a standard IP network, iSCSI moves block-level data between iSCSI initiators on servers and iSCSI targets on storage devices. When an iSCSI initiator connects to an iSCSI target, the server's operating system sees the storage as a local SCSI device that can be formatted and accessed as usual. The underlying storage is transparent to operating systems, applications, and hardware. The iSCSI processing stack is shown in the figure above.
Since iSCSI provides access to storage at the block level, heterogeneous servers and applications can share the same storage resources to maximize IT investments and simplify management. On the performance front, running an iSCSI SAN on Gigabit Ethernet can deliver performance comparable to a 1Gbps Fibre Channel SAN.
Storage consolidation allows storage devices and servers to be acquired, managed, and upgraded independently. In a consolidated storage environment, numerous heterogeneous servers and applications share a single pool of storage on a network. A consolidated infrastructure can lower management costs and results in easy scalability, high availability, and efficient capacity utilization. It can also simplify backup and disaster-recovery strategies. An additional benefit of consolidated storage is that costs can be divided between various departments and groups that use the storage. See figure above for an example of a consolidated solution.
Today, IT departments need a consolidated storage solution for their companies' business applications that includes many of same functions as high-end SANs, but at a lower cost and without excessive administrative overhead. To lower the TCO of IT infrastructure, businesses' storage costs must be parallel to their application and server investments.
iSCSI solutions vary in features and capabilities, but most include seamless expandability, automatic load balancing, automatic storage provisioning, disaster tolerance, and replication.
Once storage is consolidated, users still need a way to manage the storage. Storage virtualization simplifies tasks such as setup, storage allocation, load balancing, RAID configuration, backup, replication, and snapshots. Virtualization abstracts physical layouts and constraints of the underlying storage hardware. The decoupling of physical storage from logical volumes makes these normally disruptive activities transparent to hosts. By disassociating the physical disks from the "logical volumes" presented to hosts, administrators are no longer bound by disk capacity and performance, nor are they forced to cable or lay out data across devices every time workloads change.
Virtualization masks the underlying intricacy of the storage environment by providing a "pool" of protected storage, not just a set of consolidated disks. Loads are automatically balanced and logical volumes can be easily created and expanded on-demand and with no user impact. RAID configuration and backup, replication, and snapshot capabilities are integrated and transparent to applications.
Regardless of the approach to virtualization, iSCSI SAN solutions often provide
- Scalable, highly available pool of storage;
- Storage allocation and resizing on-demand;
- Centralized management with remote access;
- Security that protects logical volumes from unauthorized access;
- Automatic load balancing for performance optimization;
- Snapshots and replication;
- Host platform independence; and
- Multi-path host access.
Businesses must design a storage strategy that couples cost considerations with overall system management and longer-term business objectives. Using an iSCSI SAN can be an effective method for implementing such a storage strategy.
Eric R. Schott is director of product management at EqualLogic (www.equallogic.com) in Nashua, NH.