Chapter 5 Basic Functions
5.1 Data Protection
5.1.3
Redundant Copy
When the Disk Patrol function decides that preventative maintenance is required for a drive, the Redundant
Copy function uses the remaining drives to re-create the data of the maintenance target drive and writes the
data to the hot spare. The Redundant Copy function enables data to be restored while maintaining data
redundancy.
Figure 5.3 Redundant Copy function
RAID5 (Redundant)
RAID5 (Redundant)
If a bad sector is detected when a drive is checked, a replacement track is automatically allocated. This drive
is not recognized as having a drive failure during this process. However, the drive will be disconnected by the
Redundant Copy function if the spare sector is insufficient and the problem cannot be solved by allocating a
replacement track.
Sign of
failure
Disconnected
ETERNUS DX80 S2/DX90 S2 Disk storage system Overview
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Creates data from the drives other than
the maintenance target drive, and
writes data into the hot spare.
Hot spare
Disconnects the maintenance target drive
and switches it to the hot spare.
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