Initialization; Hot Spare Drive(S) - Promise Technology VTRAK E610f Product Manual

• GB Truncate – (Default) Reduces the useful capacity to the nearest
1,000,000,000 byte boundary.
• 10GB Truncate – Reduces the useful capacity to the nearest 10,000,000,000
byte boundary.
• Group Rounding – Uses an algorithm to determine how much to truncate.
Results in the maximum amount of usable drive capacity.
• Table Rounding – Applies a predefined table to determine how much to
truncate.
Capacity Coercion also affects a replacement drive used in a disk array.
Normally, when an physical drive fails, the replacement drive must be the same
capacity or larger. However, the Capacity Coercion feature permits the
installation of a replacement drive that is slightly smaller (within 1 gigabyte) than
the remaining working drive. For example, the remaining working drives can be
80.5 GB and the replacement drive can be 80.3, since all are rounded down to
80 GB. This permits the smaller drive to be used.
Without Capacity Coercion, the controller will not permit the use of a replacement
physical drive that is slightly smaller than the remaining working drive(s).

Initialization

Initialization is done to logical drives after they are created from a disk array.
Initialization sets all data bits in the logical drive to zero. The action is useful
because there may be residual data on the logical drives left behind from earlier
configurations. For this reason, Initialization is recommended for all new logical
drives. See "Initializing a Logical Drive" on page 137.

Hot Spare Drive(s)

A hot spare is a disk drive that is connected to the disk array system but is not
assigned as a member of the disk array. In the event of the failure of a drive
within a functioning fault tolerant disk array, the hot spare is activated as a
member of the disk array to replace a drive that has failed.
VTrak will replace a failing disk drive in a disk array with an unassigned drive, if
one is available. The unassigned drive is not part of any disk array. Such a drive
is called a hot spare drive. There are two types:
• Global – An unassigned disk drive available to any disk array on the VTrak.
When you initialize a logical drive, all the data on the logical drive
will be lost. Backup any important data before you initialize a
logical drive.
Chapter 7: Technology Background
Caution
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