Devices have inconsistent logical block sizes while adding VDO device

  • While extending VG on SD or VDO devices, you may get an error:

# vgextend vg1 /dev/mapper/vdo2
Devices have inconsistent logical block sizes (512 and 4096).

  • In the above output, vgextend fails due to inconsistent block size of physical volume on disk drives.
  • To resolve this issue, enable allow_mixed_block_sizes in lvm.conf to allow the same VG to have two PV of varying block sizes. The default value of allow_mixed_block_sizes is 0, which is disabled by default.

# cat /etc/lvm/lvm.conf | grep -i "allow_mixed_block_sizes" | grep -v "#"
allow_mixed_block_sizes =1

  • You can verify the block size of the SD or VDO disk using the following command:

# parted /dev/sdb u s p

Note: The default logical block size of the VDO device is 4096K (8 sectors).

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