Disadvantages

• The levels of indirection that volume managers introduce can complicate the boot process and make disaster recovery difficult, especially when the base operating-system and other essential tools are themselves on an LV.
• Logical volumes can suffer from external fragmentation when the underlying storage devices do not allocate their PEs contiguously. This can reduce I/O performance on slow-seeking media (such as magnetic disks), which have to seek over the gaps between extents during large sequential reads or writes. Volume managers which use fixed-size PEs, however, typically make PEs relatively large (a default of 4MB on the Linux LVM, for example) in order to amortize the cost of these seeks.