HP XC System Software Administration Guide Version 3.1

Two SATA disk drives, /dev/sda and /dev/sdb are shown in this example.
Follow these steps to replace the RAID disk:
1. Examine the array.
You can use the cat /proc/mdstat command or use the mdadm command to return useful
information, as shown here:
# cat /proc/mdstat
Personalities : [raid0] [raid1]
md2 : active raid0 sdb2[1] sda2[0]
35128704 blocks 64k chunks
md3 : active raid0 sdb3[1] sda3[0]
22833664 blocks 64k chunks
md1 : active raid1 sdb1[1] sda1[0]
292608 blocks [2/2] [UU]
unused devices: <none>
# mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a82b4dfc
Version : 00.90.00
UUID : eead90a0:35c0bf46:0619b26b:2d745a4d
Creation Time : date and time
Raid Level : raid1
Device Size : 292608 (285.75 MiB 299.63 MB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1
Update Time : date and time
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : 2bb - expected 15abed0f
Events : 0.10
Number Major Minor RaidDevice State
this 1 8 17 1 active sync /dev/sdb1
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
2. Determine what caused the error.
NOTE: On the HP XC system, if a single partition fails, you must replace the whole disk with an
identical one.
3. Use the mdadm command to fail (that is, to mark as faulty) all the RAID partitions on the disk. The
disk in this example has three partitions. Use the following commands to fail each partition:
# mdadm /dev/md1 -f /dev/sdb1
# mdadm /dev/md2 -f /dev/sdb2
# mdadm /dev/md3 -f /dev/sdb3
21.4 Software RAID Disk Replacement 247