Configure Hot Spares; Automatic Configuration - Started - IBM DS3000 Introduction And Implementation Manual

7065Admin_Configure.fm
The configuration proceeds in the background, Figure 8-32 on page 156.
Click OK to return to the main configuration tab.
Figure 8-32 Automatic Configuration - Started

8.3.2 Configure Hot Spares

Hot spare drives provide additional protection in case of a disk drive fault in a fault tolerant
array (RAID 1, 3, or 5). A hot-spare drive is like a replacement drive installed in advance. The
data from the failed disk drive is automatically rebuilt to the hot spare when one exists. If the
failed drive is replaced with a new drive, the data stored on the hot spare drive is copied back
to the replaced drive, and the original hot spare drive that is now in use becomes a free hot
spare drive again.
The location of a hot spare drive is fixed and does not change if it is used. A hot spare drive
defined on the DS3000 is always used as a so-called
drive can always be used for a failed drive, regardless of in which array or storage enclosure
the hot spare is located. A hot spare drive must be at least as large as the capacity of the
configured space on the failed drive, plus 512MB (if the failed disk drive is larger than the hot
spare, reconstruction is obviously not possible). The DS3000 can use a larger drive to recover
a smaller failed drive, and in this case, the remaining capacity is unavailable. The DS3000 will
first look for a hot spare drive in the same enclosure as the failed drive, of at least the same
size as the failed drive. If a suitable drive is not available in the same enclosure, it will look for
spares in other enclosures with sufficient capacity. The controller uses first suitable hot spare
drive that it finds, even if there is another drive that is a closer size match to the failed drive.
Note: There is no definitive recommendation as to how many hot spares you should install,
but it is a common practice to use a ratio of one hot spare for each wo fully populated
expansion enclosures.
To configure hot spare drives on your system click Configure Hot Spare. You can choose
between automatic and manual configuration (Figure 8-33 on page 157).
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IBM System Storage DS3000: Introduction and Implementation Guide
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global hot spare
. That is, a hot spare