When deciding where to locate file systems, you, as a system administrator, typically attempt to balance I/O load among the available disk drives. The effectiveness of this approach is limited by the difficulty of anticipating future usage patterns, as well as the inability to split file systems across the drives. For example, if a single file system receives the most disk accesses, moving the file system to another drive also moves the bottleneck to that drive.
VxVM can split volumes across multiple drives. This permits you a finer level of granularity when locating data. After measuring actual access patterns, you can adjust your previous decisions on the placement of file systems. You can reconfigure volumes online without adversely impacting their availability.