Expanding The Limits Of Storage, Virtually

As storage area networks expand, interest in storage virtualization is growing among businesses looking for ways to reduce storage costs and complexity. Storage virtualization also is shaping up as a major battleground between vendors such as EMC Corp. and IBM.

In a briefing last week, IBM executives outlined plans to expand the capabilities of the company's storage-virtualization products, including extending its SAN File System, which manages files in storage area networks, to incorporate tape storage. Later this year, IBM will provide a way for customers to use logical partitioning, where a single physical-storage device operates as two to allow data-intensive applications to run directly within a storage system to speed data retrieval.

Storage virtualization is being touted as a way to facilitate information-life-cycle management, the movement of files between expensive disk arrays and low-cost media for data archiving, and to shield applications from underlying physical-storage systems. It combines storage systems from multiple vendors into a single storage pool for greater utilization of disk arrays.

Storage virtualization enhances our ability to perform information-life-cycle management, says Brian Perlstein, IT technical architect at Oakwood Healthcare System, a health-care network that's been using IBM's storage-virtualization technology since November to create a virtual 16-terabyte storage pool for document management and other applications.

IBM wasn't the only vendor talking up storage virtualization last week. Network Appliance Inc. upgraded its V-Series storage-virtualization system, giving it the ability to more easily connect to back-end disk arrays. EMC plans to launch Storage Router, its storage-virtualization product, this summer.

Early adopters of storage-virtualization technology have achieved average cost reductions of 24% in hardware, 16% in software, and 19% in SAN administration, according to a 2004 survey of 210 IT managers by Enterprise Strategy Group. Nearly all (96%) of the respondents expressed an interest in implementing storage virtualization during the next 24 months.

IBM said that 1,000 customers, mostly small-to-midsize businesses, have deployed its SAN Volume Controller, its core storage-virtualization product that moves blocks of data between IBM and other vendors' storage systems. Those customers are typically managing virtual storage pools of 50 to 100 terabytes.

Large companies also are looking at virtualization. Commerzbank AG, one of Germany's largest banks, is considering using SAN Volume Controller and logical partitioning to manage 450 terabytes of storage capacity on 13 IBM DS8000 systems it bought last week, says Tom Hawk, IBM's enterprise storage general manager.

At Oakwood Healthcare, SAN Volume Controller already has simplified database replication and system upgrades, Perlstein says. Replicating databases stored on multiple systems used to require lots of CPU horsepower and system downtime. Using SAN Volume Controller, Perlstein creates a virtual storage system that lets replication be performed without affecting users.

The health-care network also is testing SAN File System to create data-retention policies under which frequently accessed files are stored on disk and seldom-accessed files are moved to tape.