DD200 Restorer and Axion are the only two object-based products aimed squarely at backup. DD200 Restorer stores the incoming backup data as a file and then, in the background, breaks the file into individual 4K or 8K segments, and creates a unique data object for each segment. The product then verifies if that object already exists. If it doesn't exist, DD200 Restorer stores the new object and records its existence in its database. If it exists, DD200 Restorer records the object's occurrence in its product database and logical associations with other objects but doesn't store the object again.
The Axion system consists of an industry-standard server running Avamar's software and a set of intelligent agents deployed on each backup client. Users also have the option of purchasing Avamar's software and deploying it on their own compliant platforms. Avamar's approach differs from DD200 Restorer because its agent on the host server breaks apart the file's blocks and creates a digital signature by running a hash against each block of data. The agent then sends the digital signature to the backup repository to verify the originality of the blocks. If the repository determines this is a new ID, it signals the agent to send the entire block of data from the server to the backup repository. The primary advantage this approach has over DD200 Restorer is that it minimizes the amount of data moved across the network from the server to the repository.
Because neither of these products needs to manage large amounts of meta data, they can focus on and optimize data reduction and backup times. Frank Slootman, president and CEO of Data Domain, finds optimizing data reduction secondary to lowering backup times. "Users find data reduction interesting, but the product needs to be able to reduce the backup and restore times first," says Slootman.
Steve Degner, an IT manager at Power Integrations Inc. in San Jose, CA, was one of the early adopters of this technology. Degner found that DD200 Restorer reduced the time for his full backups from three days to one-and-a-half days and decreased his restore window from 14 hours to four hours.
From a network connectivity standpoint, Axion and DD200 Restorer use existing Ethernet IP LANs for communications. However, Avamar uses a secure SSL TCP/IP socket to send the backup data, while DD200 Restorer presents a standard NFS/CIFS interface as a target to the backup software.
The major difference--and it's a big one--between Axion and DD200 Restorer is how they interact with existing backup software. Avamar requires users to either replace their existing backup software agent with the Axion agent or to deploy Avamar's agent in addition to their existing backup software agent to work with Axion. The rationale behind this architecture is to compress the backup traffic at the host level, reducing the amount of network traffic.
"Avamar wants customers to abandon use of their backup software and tape libraries--solutions that took time, money and resources to put into place for operational backup and recovery," wrote Tony Asaro, a senior analyst at the Milford, MA-based Enterprise Strategy Group (ESG), in a recent report on Avamar. He praises the Avamar technology, but advises users to implement it in small doses, at the department level or at a remote office, before rolling it out to an entire storage environment.
Users who wish to maintain their existing backup software and use Axion will need to create two backup copies, one using their existing backup software and one using Axion. However, this approach increases network traffic, introduces more complexity into the environment and should only be considered as a short-term, stop-gap measure until the company standardizes its backup processes on Avamar.
Users with existing backup software will find DD200 Restorer a more palatable alternative. Data Domain's DD200 Restorer appliance works with backup applications such as CommVault Inc.'s Galaxy, EMC's Legato NetWorker and Veritas Software Corp.'s NetBackup and only requires backup administrators to redirect the backup output to the DD200 appliance.
Avamar and Data Domain can replicate data offsite once it's stored and compressed in a central repository, cutting down on the required bandwidth and time to transport the data. Data Domain reports that it has seen instances where bandwidth requirements for offsite replication are reduced to one-tenth that of a standard tape drive.
