Hitachi Compute Rack CR 210H User Manual page 34

Failure recovery flow
The failure recovery flow for RAID5 with five logical drives working is illustrated
below. In this illustration, two cases are explained: one with a reserve disk and
the other without a reserve disk.
DISK 1 DISK 2
DISK 1 DISK 2
DISK 1 DISK 2
DISK 1 DISK 2
DISK 1 DISK 2
Figure 3-8: A case with a reserve disk
3-12
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
An error occurred in
DISK1. Transition to
degraded mode
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
Rebuild DISK1 data to
reserved disk (DISK6)
DISK 3 DISK 4 DISK 5 DISK 6
Disk array
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