Hitachi Compute Rack CR 210H User Manual page 33

SMART copyback function
SMART copyback is a function to replace an HDD safely. If a SMART failure occurs
on an HDD in the logical drive of RAID1, 5, 6, or 10, a data of the failed HDD is
copied to a reserve disk with keeping redundancy of a logical disk.
This function decreases the outbreak probability of the failure of a logical drive
according to the failure of a further HDD under rebuilding.
However, the process performance decreases in comparison with normal state
under copying to perform data copying by SMART copyback.
DISK 1 DISK 2
DISK 1 DISK 2
DISK 1 DISK 2
DISK 1 DISK 2
Figure 3-7: SMART copyback function
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
A SMART error occurred in
DISK1. Copy DISK1 data to
reserve disk (DISK6)
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
DISK1 will be registared as failed
disk after finish a copy.
Re-run with DISK2 to DISK6
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
Replace DISK1
(failed disk) (operator)
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
System Unit Functions
Hitachi Compute Rack 210H User's Guide
Active disk
Reserved disk
Failed disk
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