Hot Spare
Hot spares are used as spare drives for when drives in a RAID group fail, or when drives are in error status.
Figure 5
Hot Spare
Hot spare
Failure
RAID group
Note
For RAID6-FR, because a RAID6-FR group reserves an area equivalent to one drive, data can be restored to
the reserved space even if a drive fails. If the reserved area is in use and an error occurs in another drive
(2nd) in the RAID group, then the hot spare is used as a spare.
■
Types of Hot Spares
The following two types of hot spare are available:
•
Global Hot Spare
This is available for any RAID group. When multiple hot spares are installed, the most appropriate hot spare is
automatically selected and incorporated into a RAID group.
•
Dedicated Hot Spare
This is only available to the specified RAID group (one RAID group).
The Dedicated Hot Spare cannot be registered in a RAID group that is registered in TPPs, FTRPs, or REC Disk
Buffers.
Note
•
Assign "Dedicated Hot Spares" to RAID groups that contain important data, in order to preferentially
improve their access to hot spares.
•
When a drive that belongs to a RAID group for which a Dedicated Hot Spare is registered fails, the
Dedicated Hot Spare is given a higher priority than the Global Hot Spares. When a drive fails and no
unused Dedicated Hot Spares are available, a Global Hot Spare is used.
■
Number of Installable Hot Spares
Installing at least one hot spare is recommended.
■
Types of Drives
If a combination of SSDs and SED SSDs is installed in the ETERNUS AF, each different type of drive requires a
corresponding hot spare. The capacity of each hot spare must be equal to the largest capacity of the same-type
drives.
2. Basic Functions
RAID Functions
29
Design Guide
Содержание ETERNUS AF S3 Series
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