Protection (Shield); Figure 18 Protection (Shield) - Fujitsu ETERNUS DX100 S4 Design Manual

2. Basic Functions
Data Protection

Protection (Shield)

The Protection (Shield) function diagnoses temporary drive errors. A drive can continue to be used
if it is determined to be normal. The target drive temporarily changes to diagnosis status when
drive errors are detected by the Disk Drive Patrol function or error notifications.
For a drive that configures a RAID group, data is moved to a hot spare by a rebuild or redundant
copy before the drive is diagnosed. For a drive that is disconnected from a RAID group, whether
the drive has a permanent error or a temporary error is determined. The drive can be used again if
it is determined that the drive has only a temporary error.
The target drives of the Protection (Shield) function are all the drives that are registered in RAID
groups or registered as hot spares. Note that the Protection (Shield) function is not available for
unused drives.
The Protection (Shield) function can be enabled or disabled. This function is enabled by default.

Figure 18 Protection (Shield)

Particular
error message
?
RAID5 (Redundant)
Suspend
Temporary
protection
Diagnosing
Hot spare
*1: If copybackless is enabled, the drive is used as a hot spare disk. If copybackless is disabled, the
drive is used as a RAID group configuration drive and copyback starts. The copybackless set-
ting can be enabled or disabled until the drive is replaced.
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
Redundant Copy
Hot spare
RAID5 (Redundant)
RAID5 (Redundant)
RAID5 (Redundant)
38
Copyright 2023 Fujitsu Limited
Data is created from the drives
that are not the target drives
for the Protection (Shield) function
and written to the hot spare.
The target drive for the Protection
(Shield) function is disconnected
temporarily and diagnosed.
If the drive is determined to be
normal after the diagnosis is
performed, the drive is reconnected
to the storage system (*1).
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