IBM reveals storage server appliance plans

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iApplianceWeb
(10/23/02, 12:28:44 PM EDT)

San Jose, Ca. -- IBM Corp. is developing a range of systems based on its mainstream servers in hopes of bolstering the uptake of storage-area networks (SANs). In a briefing at its Almaden research facility here, the company sketched plans for a box that would provide a common file system across various servers, and another that would represent IBM's entry into the hotly contested market for what's known as storage virtualization.

"People are telling us SANs are great, but they are not seeing all the benefits they expected. The industry promised a lot, and these systems will help us deliver more of that," said Bruce Hillsberg, director of software strategy and technology for IBM's storage systems group.

IBM will ship two systems next year to address that issue. A so-called Virtualization Engine is essentially a Linux-based X86 server with special software to make it easier to manage blocks of storage on a SAN. Another system, called Storage Tank, would act as a meta-data server to create a common file system on a SAN, bridging differences between diverse Unix, Windows and other file systems currently in use.

Under a project dubbed Sledrunner, IBM researchers are developing other server-based devices that would provide quality-of-service guarantees over a SAN. The company gave no timetable for the release of those products.

Initial products will be packaged as so-called appliances - specially configured 1U rack servers with preinstalled software. Versions designed as blade server cards will follow. Perhaps five years out, IBM researchers see a more radical move to a brick style of systems packaging based on arrays of modular systems stacked into mesh clusters.

IBM's Virtualization Engine will use an in-band approach in which I/O requests from a server travel through the appliance to reach hard-disk arrays. The company estimates the virtualization appliance could add about 40 microseconds in latency to an I/O request.

Other vendors such as Hewlett-Packard Co. have products that use a so-called out-of-band approach in which a system not in the I/O path from a server to a hard-disk array provides the mapping of logical to physical data locations. That approach could be less expensive to expand as systems grow. However, Hillsberg said out-of-band virtualization would require more complex server adapters and more cache in disk arrays and will not work with the least-expensive disk arrays.

The IBM approach will vie with competing offerings in the works from major and emerging storage switch and disk-array makers such as Brocade, EMC and Andiamo Systems.

Standard protocol proposed

IBM's Storage Tank appliance is essentially a clustered meta-data server to provide a single name space readable across various Windows, Solaris, Linux and proprietary IBM servers. It is based on a unique Storage Tank protocol that runs on top of Internet Protocol.

In an attempt to make the technique a standard, IBM will publish the Storage Tank protocol and provide a Linux reference design that uses it before products are shipped next year, Hillsberg said. IBM is also working with unnamed server, array and software companies to gain support for the protocol.

Separately, SGI announced earlier this year a new file system for its computers that could bridge file-level data from Sun and Windows systems. And Sun has discussed its plans for addressing the SAN file-access issue as well.

Both IBM's virtualization and Storage Tank products are in a final lab test stage and will be shipped for use in customer field trials soon, Hillsberg said. Both systems would initially appear in versions geared for 2-Gbit/second Fibre Channel SANs.

Separately, Sledrunner researchers here have developed prototypes of specialized servers that can act as gateways for collecting performance-management information and processors for service-level agreements on a SAN. Developers are now layering analysis features on top of those systems in an effort to craft a server appliance that could deliver quality-of-service guarantees for storage networks.

The goal of the project is to craft a logical storage unit with up to 100 Gbytes of capacity that can guarantee a response of 10 microseconds for traffic running at 10,000 operations/second regardless of the applications load, said Jai Menon, who oversees IBM's storage systems research.

Beyond the rack and blade products, IBM foresees a future generation of low-cost modular storage and computer bricks that stack into SANs and computer clusters. While research work continues on the storage bricks, Almaden engineers are now discussing starting a parallel project on computer bricks with counterparts in computer design at IBM's Thomas J. Watson Research Center.

"The distributed nature of the software for these modular systems is an important issue, as is the cooling and communications issues," said a researcher working on the so-called Ice Cube storage bricks. IBM is exploring both air- and water-cooled versions of the bricks.

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