Data Domain plans to roll out this week a gateway designed to make storing data on Fibre Channel storage-area networks more cost-efficient by compressing it.

The company's DD460g Enterprise Restorer appliance sits between Gigabit Ethernet server networks and Fibre Channel SANs and intercepts data. It segments incoming data, identifies it and compares it with data that has been previously stored. If incoming data is a duplicate of what has been stored, it is not stored, but a reference is created. If the data is unique, it is further compressed with Zip-style algorithms.

"If you've already invested heavily in SAN storage, you may want to use it as the back-up target," says Tony Asaro, senior analyst with the Enterprise Strategy Group. "Using the Data Domain appliance, it's pretty inexpensive to just add another shelf of drives."

Asaro says in his organization's tests of Data Domain, compression ratios were seen to improve over time. When data is first backed up, users can expect to see a 4-to-1 compression ratio. As more full backups are done, that ratio will increase to 10-to-1 and then to as much as 20-to-1, as more duplicate data is found, Asaro says.

The DD460g Enterprise Restorer offers storage capacities ranging from 15T to 200TB. It works with back-up software from Bakbone, CA, Commvault, EMC, HP, IBM and Veritas, plus EMC's Clariion and Nexsan's ATABeast arrays.

Earlier Data Domain products back up data to Gigabit Ethernet networks, but not Fibre Channel SANs.

Data Domain's appliances compete with those from Avamar, Exagrid and Network Appliance.

Data Domain was founded in 2001 by a team of storage experts from Network Appliance, VA Linux Systems and Princeton University. It has received $41 million in funding from Greylock Partners, New Enterprise Associates and Sutter Hill Ventures. The company, which says it has about 180 customers, started shipping appliances at the beginning of 2004.

The DD460g is RAID protected and is available in a 3U (5¼-inch-high) rack-mount enclosure. It has hot-pluggable disks and redundant fans. The appliance starts at $65,000.