Acer Altos RAIDWatch, Manual

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Altos RAIDWatch User Guide
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5.1.1 Definition of Terms
This section describes some of the disk array terms used in this documentation.
• Physical drives. These are the actual drives installed in the enclosures.These drives are displayed
in Physical View under the RAID View window.
• Spare drives. These are physical drives that serve as backups. When a drive fails, the spare is
automatically configured into the array, and data reconstruction will commence immediately.
Spare drives appear in darker (shaded) colors than normal drives and have a red cross
superimposed on them. Large red crosses indicate Global spares, smaller ones represent Local
spares.
• Replacement drives. These are physical drives that are manually configured into the array to
replace failed drives. In the absence of spare drives, you will need to use replacement drives to
replace defective drives before rebuilding. If a spare drive has been used to rebuild the array,
you will also need to replace the failed drive manually to create another spare with the
precaution that another drive might fail.
• Failed drives. These are physical drives that fail due to some type of error. Failed drives appear
with large red X marks on their respective icons.
• Logical drives. These drives are created using physical drives. Combining physical drives into
logical drives gives you a disk array with a certain RAID level. To view logical drives, use Logical
View under the RAID View window.
• Logical volumes. These volumes are created using logical drives. Combining logical drives into
logical volumes gives you a single logical unit with even larger capacity. Logical volumes or
their partitions are mapped to various host LUNs. To view logical volumes, use Logical View
under the RAID View window.
5.2 Operating With Spare Drives
You can assign spare drives to a particular logical drive to serve as backup drives. When a drive fails
within the logical drive, one of the spares will be automatically configured into the logical drive,
and data reconstruction onto it will immediately commence.
The following are guidelines for disk failure recovery when a spare drive is available:
• If a spare drive exists in the same logical drive, the controller will automatically mount the
spare drive and start data rebuilding in the background.
• Depending on the design of the system external to the controller, it may be possible to remove
a defective drive and replace it with a new drive without shutting down the system (hot-
swapping). Alternatively, the system can be shut down at a convenient time and the failed
drive replaced.
• The replacement drive must then be assigned as a new spare drive.