Compaq Infortrend Manuale Utente

logical drive.  If a controller fails, the host I/Os originally assigned
to the failed controller will be taken over by the existing controller.
When the controller fails back (failed controller being replaced by a
new one), logical drives will be returned to the replacement
controller in its original configuration.

With logical volume - logical volumes can also be assigned to
different controllers.  The only difference is logical volumes will be
used as base units when shifting control during controller failure.

 - this is a standard feature of Infortrend RAID

controllers.  It brings the benefits of RAID 1 (high availability)
and RAID 0 (enhanced I/O performance through striping).
Simply choose multiple drives (more than two) to compose a
RAID 1 logical drive, RAID (0+1) will be automatically
implemented.

 - a logical volume is a multi-level RAID

implementation by its own rights.  A logical volume is a logical
composition which stripes data across several logical drives (the
RAID 0 method).  A logical volume with several RAID 3
members can be considered as a RAID (3+0), or RAID 53 as
defined in "The RAID Book" (from The RAID Advisory Board).

 - a logical volume with several RAID 5 members.