mdadm_raid_1_replace_disk
Table of Contents
mdadm - replace failed RAID1 disk
Check and remove disk
- Check status:
# cat /proc/mdstat Personalities : [raid1] md125 : active raid1 sdb3[1] 450747264 blocks super 1.2 [2/1] [_U] md126 : active raid1 sdb2[1] 36949888 blocks super 1.2 [2/1] [_U] bitmap: 1/1 pages [4KB], 65536KB chunk md127 : active raid1 sdb1[1] 524224 blocks super 1.0 [2/1] [_U] unused devices: <none> - /dev/sda seems missing, check dmesg:
# dmesg |grep sda [2212380.750253] end_request: I/O error, dev sda, sector 2048 [2212380.750263] md/raid1:md127: Disk failure on sda1, disabling device.
- Or with smartctl:
# smartctl /dev/sda smartctl 6.2 2013-07-26 r3841 [x86_64-linux-3.10.0-229.1.2.el7.x86_64] (local build) Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org Smartctl open device: /dev/sda failed: No such device
- Remove the drive from the array if it isn't already removed. Seems md already diabled my drive:
messages-20150504.gz:May 3 00:41:06 kvm2 kernel: md/raid1:md126: Disk failure on sda2, disabling device. messages-20150504.gz:May 3 00:41:06 kvm2 kernel: md/raid1:md125: Disk failure on sda3, disabling device. messages-20150504.gz:May 3 01:02:01 kvm2 kernel: md/raid1:md127: Disk failure on sda1, disabling device.
- Check the serial number for the good drive:
]# smartctl -a /dev/sdb |grep -i serial Serial Number: 9WJ0MGBM
Replace drive
- Replace the failed drive, double check the serial number on the drive.
- Copy boot sector / partition table to new drive:
sfdisk -d /dev/sdb | sfdisk /dev/sda
Rebuild RAID1 array
- Put new drive in array:
mdadm /dev/md125 -a /dev/sda3 mdadm /dev/md126 -a /dev/sda2 mdadm /dev/md127 -a /dev/sda1 grub2-install --recheck /dev/sda
- Watch /proc/mdstat:
# cat /proc/mdstat Personalities : [raid1] md125 : active raid1 sda3[2] sdb3[1] 450747264 blocks super 1.2 [2/1] [_U] [>....................] recovery = 0.0% (121856/450747264) finish=6938.0min speed=1082K/sec md126 : active raid1 sda2[2] sdb2[1] 36949888 blocks super 1.2 [2/1] [_U] resync=DELAYED bitmap: 1/1 pages [4KB], 65536KB chunk md127 : active raid1 sda1[2] sdb1[1] 524224 blocks super 1.0 [2/1] [_U] resync=DELAYED unused devices: <none>
Speed up rebuild
- Show current min/max limit:
sysctl dev.raid.speed_limit_min sysctl dev.raid.speed_limit_max
- Increase speed:
sysctl -w dev.raid.speed_limit_min=100000
mdadm_raid_1_replace_disk.txt · Last modified: 2021/10/09 15:14 by 127.0.0.1