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Moving older or less valuable data to slower, less-expensive media is another time-honored way to reduce costs. Comparatively low-cost SATA drives can cost as little as one-tenth the price of high-performance Fibre Channel (FC) drives, while using far less power and offering much greater density than FC drives, Forrester Research's Reichman said. SATA drives can be particularly effective when used with other features such as thin provisioning and wide striping.
Storage Switzerland's Crump advises not getting bogged down in a tiered storage strategy. "Take the oldest data you have and just move it," he said. "If nobody has accessed it in two years, the chances of anyone accessing it again are between slim to none." By avoiding the cost of designing a more formal policy, he said, "you can handle the [rare] time when someone" actually needs an older file.
Within the next 12 months, Gartner's Cox said, vendors will start allowing customers to move not just volumes but individual pages within a data set to slower, less-expensive storage as those pages become less important or go longer without being accessed. Automated tiered storage as this "sub--volume" level, he said, "is going to have a big impact on storage efficiency."
Wide striping is a variation on RAID in which data is distributed among multiple disks, using only a relatively small amount of the capacity of each disk to maximize its
"3PAR, Compellent and NetApp have all been doing wide striping for some time, and all of them are claiming the ability to derive high performance from SATA drives," he said. EMC and Hitachi Data Systems also provided disk pooling and wide striping when they released thin provisioning capabilities several years back, he said, but don't stress the use of SATA disks as much as other vendors.
In some "wide striping" solutions, the most frequently accessed data is stored automatically on the outer tracks of the disk so it's accessed most quickly, with other less-frequently used data stored elsewhere to make the most use of all the available capacity.
Rob DiStefano, IT systems manager at Earth Rangers Foundation, a Woodbridge, Ontario, non-profit organization, used this capability in the company's Pillar Data Systems' Pillar Axiom 600 to boost disk utilization to 80% vs. only 40% on older network-attached storage (NAS). Using Pillar's drag-and-drop interface, DiStefano said, he was also able to reduce his administration costs by a factor of 10.
This was first published in September 2009