The late comedian George Carlin used to do a routine that defined a home as “a place to put your stuff.” As it unfolded, the bit talked about the increasing accumulation of “stuff” and how eventually one needed to purchase a bigger home because one had “more stuff.”
The amount of data required by enterprises in order to operate could certainly fall into this humorous category. As computing has become more sophisticated, the volume of “stuff” needed to be kept and analyzed has grown dramatically, and so has the problem of efficiently storing and accessing it all. Storage Area Networks (SANs) solved the problem of isolated storage arrays and their accessibility from all applications; these arrays are networked together in such a way that the entire SAN is viewed as a series of “virtual disk drives,” each easily accessible from anywhere. In addition to access, benefits include simplified administration, scalability and flexibility.
There is one crucial factor that, if not properly and effectively addressed, can however bring SAN efficiency to a crawl, and that is file fragmentation. Since the SAN is “seen” by the OS and applications as logical drives, an I/O request processed by the file system has a number of attributes that must be checked, costing valuable system time. Fragmentation causes an application to issue multiple unnecessary I/O requests, keeping the processor busier than needed. Additionally, once an I/O request has been issued, the RAID hardware and software must process it and determine to which physical member the I/O request must be directed. With all the additional I/O requests, performance is greatly effected.
Today’s data centers are usually up 24X7, and are a terrific hotbed of activity without the added strain of fragmentation. SANs need to be maintained at maximum performance, period; fragmentation must be constantly addressed so that is simply eliminated. The “traditional” approach of scheduling defrag simply won’t work when there are few time windows in which to schedule maintenance—and in between such times fragmentation continues to build and hamper SAN performance.
The only true solution for SAN fragmentation is one that works fully automatically and invisibly, in the background. Because it utilizes only otherwise-idle resources, it requires no scheduling at all and has no negative impact on system processes. Fragmentation is no longer a problem, and SAN performance and reliability are fully maximized.
A SAN is one of the ultimate solutions for an enterprise to store and easily access their “stuff.” Make sure it is always quickly and reliably accessible by choosing the right fragmentation solution from the start.
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