Redundant Copy; Figure 13 Redundant Copy Function - Fujitsu ETERNUS DX100 S4 Design Manual

2. Basic Functions
Data Protection
Drives that are stopped by Eco-mode are checked when the drives start running again.
•
• The Disk Drive Patrol function is suspended during a drive sanitization. After drive sanitization is
completed for all the target drives in the ETERNUS DX, the Disk Drive Patrol function is re-
sumed.
The Maintenance Operation privilege is required to set detailed parameters.

Redundant Copy

Redundant Copy is a function that copies the data of a drive that shows a possible sign of failure to
a hot spare.
When the Disk Patrol function decides that preventative maintenance is required for a drive, the
data of the maintenance target drive is re-created by the remaining drives and written to the hot
spare. The Redundant Copy function enables data to be restored while maintaining data redundan-
cy.

Figure 13 Redundant Copy Function

RAID5 (Redundant)
RAID5 (Redundant)
Disconnected
If a bad sector is detected when a drive is checked, an alternate track is automatically assigned.
This drive is not recognized as having a sign of 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 assigning an alternate track.
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
Sign of
Hot spare
failure
33
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Creates data from the drives other than
the maintenance target drive, and writes
data into the hot spare.
Disconnects the maintenance target drive
and switches it to the hot spare.
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