Drive Failure; Drive Replacement - OWC Mercury Elite Pro Dual Assembly Manual And User Manual

is a limitation of the operating systems' support for the SATA chipset in the Mercury
Elite Pro Dual. Independent drive mode does not have this limitation when used over
USB.
Span Mode:
The drives show up as one large single volume. The total size will depend on the drives
installed; you can use drives of different capacities. A span is a configuration (not RAID) in
which the data is written sequentially across the drives. This combines the capacities of
the drives, but it does not provide any performance or redundancy benefits.
RAID 0 "Drive Striping" Mode:
The drives show up as one large single volume with a size equal to the combined capaci-
ties of both drives. RAID 0 is used when speed is the primary objective, but it does not
have any redundancy for protection. Data is alternated very quickly across both drives
to gain speed by distributing the workload. This allows for the fastest data transfer rates,
but if one drive fails, the whole array can become corrupted and data will be lost. Always
maintain a backup of your data!
RAID 1 "Drive Mirroring" Mode:
The drives show up as one volume with a size equal to the capacity of one of the two
drives used in the array. RAID 1 copies (or "mirrors") a set of data from the first drive to the
second drive. This is useful when reliability and redundancy are more important than ca-
pacity. When one drive fails, it can be replaced and the data will be rebuilt automatically.

2.4 DRIVE FAILURE

In the event that one of the drives fails, the corresponding drive LED will turn solid red. If
the Mercury Elite Pro Dual was configured as a RAID 0 or span, the data on the array is lost
and the volume cannot be used. In a span, only the data stored on the failed drive is lost,
although data recovery software will be required to recover the data from the other drive in
the span. If the drives were configured independently, then the data on the drive that did
not fail will remain intact.

2.4.1 Drive Replacement

If the drive was part of a RAID 1, it can be replaced and the array will be rebuilt. In the
meantime, the data will remain accessible through the other drive in the RAID 1. If the
Mercury Elite Pro Dual was purchased with drives already installed and it is still under
warranty, see Section 3.6 for information on how to contact OWC technical support to
arrange for replacement.
If the unit is outside its warranty or was purchased without drives, follow the assembly
instructions in Section 2.2 to access and replace the failed drive. If the HDD2 LED is
blinking red, the failed drive is the one on the bottom, connected directly to the black
SATA connector on the circuit board of the Mercury Elite Pro Dual (see Section 2.2, step
4). If the HDD1 LED is blinking red, the failed drive is the one on the top, connected using
OWC MERCURY ELITE PRO DUAL
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SYSTEM SETUP