Fujitsu Eternus DX80 S2 - Disk Patrol; Figure 5.2 Disk Check

Chapter 5 Basic Functions
5.1 Data Protection
ETERNUS DX80 S2/DX90 S2 Disk storage system Overview
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5.1.2 Disk Patrol
The Disk Patrol function regularly diagnoses and monitors the operational status of all disks that are installed
in the ETERNUS DX Disk storage system. Disks are checked (read check) regularly as a background process.
For disk checking, read check is performed sequentially for a part of the data in all the disks. If an error is
detected, data is restored using disks in the RAID group and the data is written back to another block of the
disk in which the error occurred.
Figure 5.2 Disk check
Disks that are stopped by Eco-mode are checked when the disks start running again.
RAID group
D1
Data is read and
checked.
D1
Data
reconstruction
D1
D2
D3
P
RAID group
Error
detection
The data is written back
to another block.
Error
D1 to D3:
P:
Data
Parity
D1