Protection (Shield); Figure 18 Protection (Shield) - Fujitsu ETERNUS AF250 Design Manual

1. Function
Data Protection

Protection (Shield)

The Protection (Shield) function diagnoses temporary drive errors. A drive can continue to be used if it is deter-
mined 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 regis-
tered 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
?
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 setting can be enabled or
disabled until the drive is replaced.
Redundant Copy
RAID5 (Redundant)
RAID5 (Redundant)
RAID5 (Redundant)
RAID5 (Redundant)
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays Design Guide (Basic)
Copyright 2019 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.
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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