Disk Battles Tape for Storage Supremacy

Administrators struggle over benefits of tape vs. disk.

Small and midsize enterprises struggling to absorb overflowing data, cost pressures and shrinking backup windows are weighing the benefits of emerging disk-based storage alternatives against tried-and-true tape-based devices.

Vendors including Unitrends Software Corp., Overland Storage Inc., StorServer Inc. and Storage Technology Corp. are addressing those obstacles with new products designed to be more reliable and a better fit with smaller customers.

Backing up his Microsoft Corp. Exchange messaging environment to tape has become an issue for Brad Ross, director of Information Security at Jefferson Pilot Communications Co., which operates several television and radio stations across the United States. "It definitely becomes an issue, especially with the news, our time schedule, the [inflexibility] with Microsoft to do backups," said Ross in Charlotte, N.C. "You cant always get what you want from that."

Ross is testing Unitrends refreshed line of DPUs (Data Protection Units), which were rolled out last week. The disk-based backup appliances are offered as a desktop configuration that accommodates between 250GB and 400GB of data but can scale to 9.6TB as a 5U (8.75-inch) rack-mountable multiprocessor system.

The integrated software and hardware technology also features bare-metal restore capabilities, said Unitrends officials in Columbia, S.C.

Also looking to offer a nimbler backup and recovery alternative to tape autoloaders, Overland last week introduced its disk-based REO 1000 appliance. Aimed for distribution through the VAR channel, the REO 1000 features 1TB of data storage capacity, provides data redundancy and performs faster data restorations than tape because it is disk-based, according to Overland officials in San Diego.

Typically, IT administrators who rely on tape autoloaders or a stand-alone tape drive for backup dont get the same file retrieval and data restoration speed as those who use disk-based systems because tape devices lack disks RAID and iSCSI (Internet SCSI) capabilities, say industry analysts. The REO 1000 offers embedded iSCSI connectivity, RAID data protection and LTO2 (Linear Tape Open 2) tape emulation. The appliance also can partition 1TB of data into 16 blocks.

Meanwhile, StorServer recently announced the companys smallest online disk appliance, the StorServer D1 Backup Appliance, which is equipped with a self-install guide and employs Microsofts Windows Storage Server 2003. The StorServer product is rack-mountable in a 4U (7-inch) space and keeps a full online backup in its SATA (serial ATA) disk array, said StorServer officials in Colorado Springs, Colo. The D1 appliance features one 150GB storage pool that can be expanded by 500GB more.

To reconcile the plummeting price of disk-based backup versus the still-high costs of tape, tape vendors must incorporate technologies such as iSCSI and some type of fabric awareness into their wares, said Bob Zimmerman, an analyst at Forrester Research Inc., in Cambridge, Mass.

Due later this year, StorageTeks StreamLine SL500 automated tape system borrows technology from the companys SL8500 modular library system, which is designed to provide ILM (information lifecycle management) capabilities. The SL500 holds 30 to 50 modular slots and robotics in the base unit. Expansion modules carry 90 to 130 slots with four drive bays in a standard rack, said company officials in Louisville, Colo. The product also enables remote monitoring and capacity-on-demand provisioning and supports LTO/SDLT (Super Digital Linear Tape) formats and Fibre Channel connectivity.

Rance Petty, network support manager at FlightSafety International Inc., said the rising price of tape relative to disk is leading his organization to examine consolidating all its backups onto disk—but it wont be easy. "The cost of tape is too expensive, and disk prices have gone down. Disk is more reliable to tape, faster and cheaper," said Petty, in Broken Arrow, Okla. However, switching to disk brings with it its own headaches, Petty said.

"The problems were running into is we dont have enough bandwidth on our T-1 lines, so were looking at additional bandwidth so we can back up to disk off-site," Petty said.


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