Rebuild; Figure 12 Rebuild - Fujitsu ETERNUS DX S5 Series 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 12 Rebuild
Failure
Disconnection
Failed drive
Note
When no hot spares are registered, rebuilding processes are only performed when a failed drive is
replaced or when a hot spare is registered.
IMPORTANT
• Rebuild Speed
The priority of the rebuild operations with respect to host access can be specified. By setting "Rebuild
Priority" to "High", rebuild operations are given priority over host access and the performance of the
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.
Refer to "Modify RAID Group Parameters" in "ETERNUS Web GUI User's Guide" for details.
Rebuild
RAID5 (No redundancy)
RAID5 (Redundant)
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Disconnects the failed drive from 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.
Design Guide