Disk Drive Patrol; Figure 12 Disk Drive Patrol - Fujitsu ETERNUS DX100 S4 Design Manual

2. Basic Functions
Data Protection
The T10-DIF function can be used when connecting with HBAs that support T10-DIF with an FC in-
terface.
The T10-DIF function can be enabled or disabled for each volume when the volumes are created.
This function cannot be enabled or disabled after a volume has been created.
The T10-DIF function can be enabled only in the Standard volume.
•
LUN concatenation cannot be performed for volumes where the T10-DIF function is enabled.
•

Disk Drive Patrol

In the ETERNUS DX, all of the drives are checked in order to detect drive errors early and to restore
drives from errors or disconnect them.
The Disk Drive Patrol function regularly diagnoses and monitors the operational status of all drives
that are installed in the ETERNUS DX. Drives are checked (read check) regularly as a background
process.
For drive checking, read check is performed sequentially for a part of the data in all the drives. If an
error is detected, data is restored using drives in the RAID group and the data is written back to
another block of the drive in which the error occurred.

Figure 12 Disk Drive Patrol

Data is read and
checked.
The data is written
back to another block.
Read checking is performed during the diagnosis.
These checks are performed in blocks (default 2MB) for each drive sequentially and are repeated
until all the blocks for all the drives have been checked. Patrol checks are performed every second,
24 hours a day (default).
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
Error detection
Error
D1
RAID group
Data reconstruction
D1
D1
D2 D3
D1
RAID group
D1 to D3: Data
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