Replace a working RAID device

You can replace a working RAID device in a logical volume by using the --replace argument of the lvconvert command.

Before you begin

  • The RAID device has not failed. Warning
    In the case of RAID device failure, the following commands do not work.

Procedure

  1. Create a RAID1 array: 
    # lvcreate --type raid1 -m 2 -L 1G -n my_lv my_vg
     
      Logical volume "my_lv" created
  2. Examine the created RAID1 array: 
    # lvs -a -o name,copy_percent,devices my_vg
     
      LV               Copy%  Devices
  my_lv            100.00 my_lv_rimage_0(0),my_lv_rimage_1(0),my_lv_rimage_2(0)
  [my_lv_rimage_0]        /dev/sdb1(1)
  [my_lv_rimage_1]        /dev/sdb2(1)
  [my_lv_rimage_2]        /dev/sdc1(1)
  [my_lv_rmeta_0]         /dev/sdb1(0)
  [my_lv_rmeta_1]         /dev/sdb2(0)
  [my_lv_rmeta_2]         /dev/sdc1(0)
  3. Replace the RAID device with any of the following methods depending on your requirements:
    1. Replace a RAID1 device by specifying the physical volume that you want to replace: 
      # lvconvert --replace /dev/sdb2 my_vg/my_lv
    2. Replace a RAID1 device by specifying the physical volume to use for the replacement: 
      # lvconvert --replace /dev/sdb1 my_vg/my_lv /dev/sdd1
    3. Replace multiple RAID devices at a time by specifying multiple replace arguments: 
      # lvconvert --replace /dev/sdb1 --replace /dev/sdc1 my_vg/my_lv

Results

  1. Examine the RAID1 array after specifying the physical volume that you wanted to replace: 
    # lvs -a -o name,copy_percent,devices my_vg
     
      LV               Copy%  Devices
  my_lv             37.50 my_lv_rimage_0(0),my_lv_rimage_1(0),my_lv_rimage_2(0)
  [my_lv_rimage_0]        /dev/sdb1(1)
  [my_lv_rimage_1]        /dev/sdc2(1)
  [my_lv_rimage_2]        /dev/sdc1(1)
  [my_lv_rmeta_0]         /dev/sdb1(0)
  [my_lv_rmeta_1]         /dev/sdc2(0)
  [my_lv_rmeta_2]         /dev/sdc1(0)
  2. Examine the RAID1 array after specifying the physical volume to use for the replacement: 
    # lvs -a -o name,copy_percent,devices my_vg
     
      LV               Copy%  Devices
  my_lv             28.00 my_lv_rimage_0(0),my_lv_rimage_1(0)
  [my_lv_rimage_0]        /dev/sda1(1)
  [my_lv_rimage_1]        /dev/sdd1(1)
  [my_lv_rmeta_0]         /dev/sda1(0)
  [my_lv_rmeta_1]         /dev/sdd1(0)
  3. Examine the RAID1 array after replacing multiple RAID devices at a time: 
    # lvs -a -o name,copy_percent,devices my_vg
     
      LV               Copy%  Devices
  my_lv             60.00 my_lv_rimage_0(0),my_lv_rimage_1(0),my_lv_rimage_2(0)
  [my_lv_rimage_0]        /dev/sda1(1)
  [my_lv_rimage_1]        /dev/sdd1(1)
  [my_lv_rimage_2]        /dev/sde1(1)
  [my_lv_rmeta_0]         /dev/sda1(0)
  [my_lv_rmeta_1]         /dev/sdd1(0)
  [my_lv_rmeta_2]         /dev/sde1(0)