Rebuild; Figure 15 Rebuild - Fujitsu ETERNUS DX500 S4/DX600 S4 Design Manual

2. Basic Functions
Data Protection

Rebuild

Rebuild processes recover data in failed drives by using other drives. If a free hot spare is available when one of
the RAID group drives has a problem, data of this drive is automatically replicated in the hot spare. This ensures
data redundancy.

Figure 15 Rebuild

Failure
Disconnection
Failed drive
When no hot spares are registered, rebuilding processes are only performed when a failed drive is replaced or
when a hot spare is registered.
Rebuild Speed
•
Giving priority to rebuilding over host access can be specified. By setting a higher rebuild priority, the per-
formance of rebuild operations may improve.
However, it should be noted that when the priority is high and a rebuild operation is performed for a RAID
group, the performance (throughput) of this RAID group may be reduced.
FUJITSU Storage ETERNUS DX500 S4/DX600 S4, ETERNUS DX500 S3/DX600 S3 Hybrid Storage Systems Design Guide (Basic)
Rebuild
RAID5 (No redundancy)
RAID5 (Redundant)
35
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Disconnects the failed drive to the ETERNUS
storage system and creates data from the drives
other than the failed drive and writes the data
into the hot spare.
Hot spare
Configures the hot spare in the RAID group.
P3AM-7722-25ENZ0