High Interest Rate Online Savings look, it can be readily seen that file fragmentation does indeed impact a SAN.
Physical members in a SAN environment are not read or written to directly by an application. Even the Windows file system sees each set of striped drives as one single drive. As an application reads and writes to this virtual environment (creating new files, extending existing ones, as well as deleting others) the files become fragmented. Because of this fact, fragmentation on each logical drive will have a substantial negative performance effect.
When an I/O request is processed by the file system, there are a number of attributes that must be checked which cost valuable system time. If an application has to issue multiple I/O requests, as in the case of fragmentation, not only is the processor kept busier than needed, but once the 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.

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