Hot Spares; Figure 10 Hot Spares - Fujitsu ETERNUS DX60 S4 Design Manual

1. Function
RAID Functions

Hot Spares

Hot spares are used as spare drives for when drives in a RAID group fail, or when drives are in error status.

Figure 10 Hot Spares

RAID group
When the RAID level is RAID6-FR, data in a failed drive can be restored to a reserved space in a RAID group
even when a drive error occurs because a RAID6-FR RAID group retains a reserved space for a whole drive in
the RAID group. 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.
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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 drive is au-
tomatically 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.
Assign "Dedicated Hot Spares" to RAID groups that contain important data, in order to preferentially improve
their access to hot spares.
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Number of Installable Hot Spares
Register one hot spare for each drive type.
FUJITSU Storage ETERNUS DX60 S4, ETERNUS DX60 S3 Hybrid Storage Systems Design Guide (Basic)
Hot spare
Failure
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