Infortrend RAID Controller Manual

To perform RAID expansion on a logical volume, expand each
member logical drive, then perform RAID expansion on the logical
volume.
Steps to expand a Logical Volume:
1. Expand each member logical drive.
2. Expand the logical volume.
3. Map the newly-added capacity (in the form of a new partition) to a
host LUN.
Is there anything changed with logical volume?
Redundant Controller:
Without logical volume - logical drives can be assigned to the
primary controller or to the secondary controller. The host I/Os
directed to a logical drive will be served by the controller to which this
logical drive is assigned. 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 the original configuration.
With logical volume - logical volumes can also be assigned to
different controllers. The only difference is that the Logical volumes
will be considered as the base units for shifting the control during a
controller failure.
A logical volume with logical drives of different
levels?
Multi-level RAID systems
1. RAID (0+1) - this is a standard feature of Infortrend RAID
controllers. It has the benefits of RAID 1 (high availability) and
RAID 0 (enhanced I/O performance through striping). Simply
choose multiple drives for a RAID 1 logical drive, the RAID
controller will implement RAID (0+1) automatically.
2. RAID (3+0) - a logical volume itself is a multi-level RAID
implementation. A logical volume is composed of one or several
logical drives with data "striping" (RAID 0). A logical volume
with several RAID 3 member logical drives can be considered as a
RAID (3+0), or RAID 53 as defined in "The RAID Book" (from The
RAID Advisory Board).
3. RAID (5+0) - a logical volume with several RAID 5 member
logical drives.
Functional Description 2-15