- Note: If your RAID array is degraded you will see something like this
cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdb1[1] sda1[0](F)
487104 blocks super 1.2 [2/1] [_U]
md1 : active raid1 sdb2[1] sda2[0](F)
976142144 blocks super 1.2 [2/1] [_U]
Get information about the hard drive(s)¶
sudo hdparm -I /dev/sda
/dev/sda:
HDIO_DRIVE_CMD(identify) failed: Input/output error
A healthy drive will show output similar to:
sudo hdparm -I /dev/sdb
/dev/sdb:
ATA device, with non-removable media
Model Number: WDC WD10EZEX-00WN4A0
Serial Number: WD-WCC6Y2ZHZJAH
Firmware Revision: 01.01A01
Transport: Serial, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
Used: unknown (minor revision code 0x001f)
Supported: 10 9 8 7 6 5
Likely used: 10
Configuration:
Logical max current
cylinders 16383 0
heads 16 0
sectors/track 63 0
--
... etc
or an alternative command
sudo lshw -class disk -class storage
... etc
*-scsi:0
physical id: 1
logical name: scsi0
capabilities: emulated
*-disk
description: SCSI Disk
physical id: 0.0.0
bus info: scsi@0:0.0.0
logical name: /dev/sda
size: 931GiB (1TB)
configuration: logicalsectorsize=512 sectorsize=512
*-scsi:1
physical id: 2
logical name: scsi1
capabilities: emulated
*-disk
description: ATA Disk
product: WDC WD10EZEX-00W
vendor: Western Digital
physical id: 0.0.0
bus info: scsi@1:0.0.0
logical name: /dev/sdb
version: 1A01
serial: WD-WCC6Y2ZHZJAH
size: 931GiB (1TB)
capabilities: partitioned partitioned:dos
configuration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=000e5fab
... etc
and another (possibly the best solution) program;
sudo smartctl -d ata -a -i /dev/sdb
... etc
=== START OF INFORMATION SECTION ===
Model Family: Western Digital Blue
Device Model: WDC WD10EZEX-00WN4A0
Serial Number: WD-WCC6Y2ZHZJAH
LU WWN Device Id: 5 0014ee 20d232e87
Firmware Version: 01.01A01
User Capacity: 1,000,204,886,016 bytes [1.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 7200 rpm
Form Factor: 3.5 inches
Device is: In smartctl database [for details use: -P show]
ATA Version is: ACS-3 T13/2161-D revision 3b
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Mon Jan 30 13:43:46 2017 EST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
... etc
Remove the failed disk from the RAID1 array¶
In this example, I have 2 disks - /dev/sda and /dev/sdb with 2 partitions on each disk /dev/sda1, /dev/sda2, /dev/sdb1, /dev/sdb2 - and /dev/sda has died. Here is what mdstat looks like
cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sdb2[1]
976142144 blocks super 1.2 [2/1] [_U]
md0 : active raid1 sdb1[1]
487104 blocks super 1.2 [2/1] [_U]
unused devices: <none>
Remove the raid devices
mdadm --manage /dev/md0 --fail /dev/sda1
mdadm --manage /dev/md1 --fail /dev/sda2
mdadm --manage /dev/md0 --remove /dev/sda1
mdadm --manage /dev/md1 --remove /dev/sda2
shutdown -h now
- Physically remove the broken disk and install the new one
Add the new disk to the RAID1 array¶
Mirror the partitioning scheme from the RAID disk to the new disk¶
sfdisk -d /dev/sdb | sfdisk /dev/sda
Add the new disk to the array¶
mdadm --manage /dev/md0 --add /dev/sda1
mdadm --manage /dev/md1 --add /dev/sda2
Check the recovery status¶
cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sda2[2] sdb2[1]
976142144 blocks super 1.2 [2/1] [_U]
[>....................] recovery = 0.3% (3282752/976142144) finish=103.7min speed=156321K/sec
md0 : active raid1 sda1[2] sdb1[1]
487104 blocks super 1.2 [2/2] [UU]
unused devices: <none>
Install GRUB to the MBR of the new disk¶
grub-install /dev/sda