Open-source storage explained

Find out why interest in open-source storage technology could grow now that Sun is promoting its Unified Storage Systems, featuring a substantial amount of open-source software.

Open-source storage software is freely available, but it's the rare IT department that's willing to cobble it together with hardware to build a storage system.

Corporations are more likely to use it by happenstance, acquiring it through storage systems they buy from major vendors, some of which embed open-source technology into their products.

Other companies are game to try software applications served up with support contracts from a scattering of small vendors, such as Zmanda Inc. and Bacula Systems SA in the backup space. And the truly industrious might ferret out nascent open-source storage projects on SourceForge.net.

Still, enterprise IT organizations are typically so worried about data loss that they tend to favor storage products from established vendors. That's why Sun Microsystems Inc.'s new  Sun Storage 7000 Unified Storage Systems, billed as "open storage appliances" and formerly known by the name Amber Road, have created a stir in the market.

Launched in November, Sun's 7000 family of storage products is based on industry-standard hardware and a software stack that includes a substantial amount of open-source technology.

Sun's open-source software

The Sun stack includes the OpenSolaris operating system, with its default ZFS file system featuring simple administration, end-to-end data integrity and scalability. OpenSolaris supports not only NFS but CIFS, through an in-kernel implementation, to enable file access with Windows-based systems. Users who prefer Samba for file-and-print services to CIFS clients can use that open-source technology.

"In terms of vendors of note, Sun is the only one that's really promoting the open-source storage approach," says Roger Cox, a research vice president in Gartner Research. "What they're trying to do is get various development communities to take their software, Solaris/ZFS, and add some modifications to it, add some value to it and create storage solutions based on that technology, which then allows Sun to make money based on maintenance."

Two vendors -- greenBytes Inc. and Nexenta Systems Inc. -- have already picked up the torch and built storage systems based on Solaris and ZFS. But it's too early to tell if Sun will be able to capitalize on the model that made Linux grow in popularity.

"It does have promise," says Cox, "in the sense that this can have a major impact in terms of reducing costs for storage, particularly in today's economic environment with people not having the kind of money they've had in the past. Storage data doesn't stop growing, and they have to replace products that have reached their [end of] lifecycle."

What caught the attention of Gene Ruth, a senior storage analyst at Midvale, Utah-based Burton Group, is the way the ZFS file system has been adjusted to leverage the capability of solid-state disk (SSD). "They're one of the first to offer solid-state disks that are uniquely integrated into the storage system," says Ruth.

ZFS automatically writes new data to the write cache located on an SSD and determines data access patterns and stores frequently accessed data on an SSD, according to Sun.

John Webster, principal analyst at Nashua, N.H.-based Illuminata Inc., says the reseller community isn't typically attracted to Sun storage, yet it appears to like the new open technology. If interest in Sun's new systems grows, that also might spark more interest in open-source storage technology in general, as the storage world continues toward commoditization.

"There's significant momentum developing behind this open-source storage movement. I don't know how far it's going to go. Certainly, there are going to be some resisters, and certainly the IT community isn't going to buy off on this concept overnight," says Webster. "But I think it's going to grow in magnitude and will become a significant threat to the more proprietary forms of storage that we now see. The IT community will always be attracted to functionality at a lower cost."

User challenges

However, users might not want to be the ones building the systems. Those who do often find they need to spend increasing levels of effort to tune and maintain them, especially if the systems are heavily customized.

Chelmsford, Mass.-based OurStage Inc., a Web site catering to new music, noticed slow storage performance six months after putting together a mixed NAS and iSCSI system using CentOS Linux, which is based on code from Red Hat Inc., running on white-box hardware from Tyan Computer Corp. and Super Micro Computer Inc. Ultimately, the tech team hit a wall in its comprehension of the causes and its attempts to tune around them.

"The farther you go, you have to put more and more work in to get less and less gain," says Mark Niedzielski, infrastructure manager at the Web startup. OurStage, which joined Sun's Startup Essentials program, now runs OpenSolaris on three white boxes and one of Sun's Storage 7210 Unified Storage boxes.

Red Hat's storage capabilities

Sun isn't the only one claiming its operating system is conducive to storage. Red Hat says its  Red Hat Enterprise Linux Advanced Platform (RHEL-AP) offers significant storage capabilities, which are embedded in storage hardware or available as layered software products.

For instance, RHEL-AP's clustered file system -- Global File System (GFS) -- provides cluster-wide, fully synchronized, parallel read/write access to shared storage, according to Nick Carr, Red Hat's marketing director.

RHEL-AP also includes a logical volume manager (LVM) to manage a large, disparate physical storage configuration as a single logical entity. Other capabilities include support for standard RAID levels, cloning, multiple read/write snapshots and multipathing.

Linux can also be used as a server with support for CIFS, NFS and iSCSI block clients, as well as support for Fibre Channel (FC), Fibre Channel over Ethernet (FCoE), iSCSI (host and target), and 10 GB Ethernet, according to Carr.

Users have the option of building their own systems or deploying a pre-built, tested, certified and supported package through a Red Hat subscription.

Open-source backup

Open-source storage doesn't stop at the operating and file systems. Zmanda, for example, espouses the Red Hat model and offers a freely downloadable community edition of its  Amanda network backup software, as well as an enterprise edition that it has sold as an annual subscription since 2007.

Zmanda CEO and founder Chander Kant says the software, which is based on an open-source project at the University of Maryland, has attracted a following at universities, small- and medium-sized businesses (SMBs), and even departments at some Fortune 1000 companies. Zmanda, which launched in 2005, finished ahead of plan in the final quarter of last year despite the failing economy, according to Kant.

"In general, what we find in these economic times is that bells and whistles aren't so important for administrators. But they do want a backup solution," says Kant.

Chris Hoogendyk, systems administrator for the biology and geology departments at the University of Massachusetts in Amherst, says the main driver for open-source storage was the cost-benefit analysis. He says he typically has to wait for a department to budget for tape libraries.

"Open source doesn't cost you an arm and a leg and, in this case, it's mature enough that it has everything you need," says Hoogendyk, who's been responsible for backup on network systems since 1992. "In addition, there's a whole issue that you've got an open and fairly large community of people who help each other and provide information and contribute to the development. And if you have any questions about how it works, you can actually open it up and look at the code."

Hoogendyk has been using the community edition of Zmanda for approximately two years and now does part-time consulting on behalf of Zmanda, providing support on its online forums.

Kant says the biggest reason customers turn to Zmanda, other than cost, is its support of open and standard formats for storing data -- tar for Linux and Unix, and ZIP for Windows. He adds that Zmanda also uses industry-standard compression and encryption algorithms.

"Systems administrators can recover their data with standard operating system utilities, even if our software isn't around," says Kant.

Zmanda's software runs on Linux or Solaris servers, and an agent runs on every system that a user wants to use. The product will use the backup media of the customer's choice, whether tape, disk array or the storage cloud, including Amazon's Simple Storage Service (S3), says Kant.

"Backup is considered a mature market, but as tapes come out of favor and technologies like backup to disk and the storage cloud become more popular, that creates a huge opportunity for vendors like us," adds Kant.

Backup software isn't the only area that open source has touched in storage. Sun, for instance, also has an open-source Storage Archive Manager that's tightly integrated with its high-performance, 64-bit Solaris SAN-based Quick File System (QFS) file system, which is also open source. Sun also maintains and supports the Lustre clustered file system.

Among the other open-source offerings are  FreeNAS software, which includes support for CIFS, NFS, iSCSI and software RAID; and Self-Monitoring, Analysis and Reporting Technology System (SMART) tools.

"For this year, there'll be a lot of talk and awareness centered around the value proposition of using open source to avoid costs. However, there needs to be better articulation of the total cost of ownership, [intellectual property] ownership and transfer," says Greg Schulz, founder and senior analyst at StorageIO Group in Stillwater, Minn. "Five years out, we should certainly see more uptake in open-source solutions in general and particularly where open-source technologies are integrated or part of commercial packaged solutions."

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