Advanced Technology and Systems Co., Ltd.
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PHYSICAL DRIVE 1 2 3 4
LOGICAL DRIVE 1 2 3 SPARE
1.4
Hot Spare Feature
When the hot spare feature is activated, background data recovery onto the spare drive starts
immediately after the failure of an on-line drive. This feature reduces the effective storage capacity of
the ArrayMasStor, since one drive is reserved as a hot spare. However, the hot spare feature improves
the ArrayMasStor’s reliability and its ability to protect data. After the data recovery process is
complete, the ArrayMasStor is redundant (fault tolerant) again.
In the following example, there are four drives in the ArrayMasStor. The hot spare feature is only
available when more than three drives are used.
When one of the on-line drives fails, the data recorded on the failed drive is re-generated and written
onto the spare drive. After the data recovery process is complete, the spare drive takes the place of
failed drive. For example, if drive #3 fails, the hot spare drive (physical drive #4) becomes logical
drive #3.
When the failed drive is replaced, the replacement drive becomes the spare drive.
PHYSICAL DRIVE 1 2 3
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LOGICAL DRIVE 1 2 SPARE 3