Copyback/Copybackless
A Copyback process copies data in a hot spare to the new drive that is used to replace the failed drive.
Figure 16 Copyback
RAID5 (Redundant)
After replacing has been completed,
copies the data from the hot spare
to the new drive.
Hot spare
RAID5 (Redundant)
After rebuilding has been completed,
replaces the failed drive with the new drive.
Failed drive
RAID5 (Redundant)
Copyback
•
Copyback speed
Giving priority to Copyback over host access can be specified. By setting a higher Rebuild priority, the per-
formance of Copyback operations may improve.
However, it should be noted that when the priority is high and a Copyback operation is performed for a
RAID group, the performance (throughput) of this RAID group may be reduced.
If copybackless is enabled, the drives that are registered in the hot spare become part of the RAID group config-
uration drives after a rebuild or a redundant copy is completed for the hot spare.
The failed drive is disconnected from the RAID group configuration drives and then registered as a hot spare.
Copyback is not performed for the data even if the failed drive is replaced by a new drive because the failed drive
is used as a hot spare.
A copyback operation is performed when the following conditions for the copybackless target drive (or hot
spare) and the failed drive are the same.
•
Drive type (SSD or SED SSD)
•
Capacity
1. Function
Data Protection
34
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays
Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AG-1822-09ENZ0
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