Dell PowerEdge RAID Controller 6i - Manual (Page 37)

About PERC 6 and CERC 6i Controllers
37
Failed Physical Disk Detection
The controller automatically detects and rebuilds failed physical disks when
a new drive is placed in the slot where the failed drive resided or when an
applicable hot spare is present. Automatic rebuilds can be performed
transparently with hot spares. If you have configured hot spares, the
controllers automatically try to use them to rebuild failed physical disks.
Redundant Path With Load Balancing Support
The PERC 6/E adapter can detect and use redundant paths to drives
contained in enclosures. This provides the ability to connect two SAS cables
between a controller and an enclosure for path redundancy. The controller is
able to tolerate the failure of a cable or enclosure management module
(EMM) by utilizing the remaining path.
When redundant paths exist, the controller automatically balances I/O load
through both paths to each disk drive. This load balancing feature increases
throughput to each drive and is automatically turned on when redundant
paths are detected. To set up your hardware to support redundant paths, see
"Setting up Redundant Path Support on the PERC 6/E Adapter" on page 56.
NOTE:
This support for redundant paths refers to path-redundancy only and not to
controller-redundancy.
Using Replace Member and Revertible Hot Spares
The Replace Member functionality allows a previously commissioned hot spare
to be reverted back to a usable hot spare. When a drive failure occurs within
a virtual disk, an assigned hot spare (dedicated or global) is commissioned and
begins rebuilding until the virtual disk is optimal. After the failed drive is
replaced (in the same slot) and the rebuild to the hot spare is complete, the
controller automatically starts to copy data from the commissioned hot spare to
the newly-inserted drive. After the data is copied, the new drive is part of the
virtual disk and the hot spare is reverted back to being a ready hot spare; this
allows hot spares to remain in specific enclosure slots. While the controller is
reverting the hot spare, the virtual disk remains optimal.
NOTE:
The controller automatically reverts a hot spare only if the failed drive is
replaced with a new drive in the same slot. If the new drive is not placed in the
same slot, a manual Replace Member operation can be used to revert a previously
commissioned hot spare.
Dell_PERC6.1_UG.book Page 37 Wednesday, April 15, 2009 4:18 PM