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Reducing backup data and managing it better is an increasing problem. The advent and growing acceptance of technologies such as virtual tape libraries (VTLs), network virtualization, ATA drives and iSCSI storage networks simplify the infrastructure and reduce the cost of housing data, but do little to solve the problem of managing data more intelligently.
By storing files as objects, object-based storage (OBS) products manage and protect data more efficiently than traditional backup products. OBS products use Ethernet interfaces and NAS protocols (such as NFS and CIFS) for ease of connectivity and to minimize the amount of data stored and the time required to retrieve it, although the techniques to do so vary among products.
Instead of storing entire files, OBS products create data objects and meta data from incoming files. By storing only the object, a company can increase its storage usage capacity and provide fast, secure, online access to archived files. All OBS products:
- Create a unique identifier for the file
- Store the same files together as one object
- Create and store meta data associated with the file
The OBS products' algorithms analyze the incoming file and then, depending on the product's underlying architecture, compress the file's blocks or store the entire file. Products such as Axion from Irvine, CA-based Avamar Technologies Inc. and DD200 Restorer from Palo Alto, CA-based Data Domain Inc. analyze the blocks that comprise each file and store them together.
Products like Archivas Cluster (ArC) from Waltham, MA-based Archivas Inc. or EMC Corp.'s Centera analyze the incoming files and create a digital signature by using a hashing algorithm (see Hashing algorithms) against the file. They then store exact copies of the entire file as one image and create an index that matches the digital signature with the stored file object.
Mike Luter, CTO at the Cancer Therapy & Research Center (CTRC) in San Antonio, uses ArC to store patients' X-rays to meet HIPAA requirements. If one byte in a patient's X-ray changes, a new file is created and stored. Because each X-ray is different, Luter sees almost no capacity optimization benefits from the Archivas product; however, he expects to see capacity gains as he begins to use it for e-mail archiving in the next few months.
When any OBS product examines an incoming file for its uniqueness, it also creates meta data that's used to manage the newly created data objects. OBS products that analyze files at the sub-block level create only a few meta data attributes, such as logical associations between blocks, because the main objective of this class of products is capacity optimization. OBS products that manage access to files create a much larger set of associated meta data, which includes file ownership, security permissions, retention and expiration dates.
For companies grappling with backup data growth, products like Axion and DD200 Restorer analyze the backup data files at the sub-block level and store them at that level. Products from companies such as Archivas, EMC, Hewlett-Packard Co. and Cambridge, MA-based Permabit Inc. address issues such as e-mail, medical record archiving and legal compliance. Their products analyze and store the file based upon the content of the entire file, not just certain blocks of the file.
This was first published in July 2005