Allen of i365 says the benefits of compression vary. It can reduce data by ratios of 6:1 or more for SQL databases, but for file servers the ratios are closer to 2:1. According to Fadi Albatal, vice president of marketing at FalconStor, compression is most effective on backup, secondary or tertiary storage, where it can reduce storage needs by ratios of 2:1 to 4:1 for "highly active" database or e-mail applications. When information management services firm Iron Mountain Inc. archives applications, compression and deduplication reduce storage by as much as 80 per cent, says T.M. Ravi, Iron Mountain's chief marketing officer.
IBM focused attention on compression of primary storage with its acquisition of Storwize, whose appliance writes compressed files back to the NAS device on which they originated or to another tier of storage. Storwize is beta-testing a block-based appliance, says Doug Balog, vice president of IBM storage.
Files compressed by Microsoft Office applications or popular image formats such as JPEG can't be reduced with many common compression techniques or may even increase in size. Neuxpower Solutions Ltd. claims that its software can shrink Office and JPEG files by as much as 95% without loss of image quality by removing unnecessary information such as metadata or details that can't be seen unless the image is enlarged. Ocarina, which is being acquired by Dell, says its products offer similar capabilities because they use multiple optimization algorithms tuned for different types of content, and they have the ability to test and choose among various compression methods for the best runtime efficiency.
Deduplication and compression are complementary. "Use compression when the primary focus is on speed, performance, transfer rates. Use deduplication where there is a high degree of redundant data and you want higher space savings," says Schulz.
3. Policy-Based Tiering
Policy-based tiering is the process of moving data to different classes of storage based on criteria such as its age, how often it is accessed or the speed at which it must be available. Unless the policy calls for the outright deletion of unneeded data, this technique won't reduce your overall storage needs, but it can trim costs by moving some data to less expensive, but slower, media.
Vendors in this market include Hewlett-Packard Co., which offers built-in policy management and automated file migration in its StorageWorks X9000, and DataGlobal GmbH, which says that its unified storage and information management software enables customers to analyze and manage unstructured files and other information and thereby reduce their storage needs by 60 per cent to 70 per cent for e-mail and about 20 per cent for file servers.
Other products with tiering capabilities include Storage Center 5 from Compellent Technologies, HotZone and SafeCache from FalconStor, Policy Advisor from 3Par, EMC's FAST and F5 Networks' ARX series of file virtualization appliances.
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