5.2. Resizing an Online Multipath Device

If you need to resize an online multipath device, use the following procedure.
  1. Resize your physical device.
  2. Execute the following command to find the paths to the LUN:
    # multipath -l
  3. Resize your paths. For SCSI devices, writing a 1 to the rescan file for the device causes the SCSI driver to rescan, as in the following command:
    # echo 1 > /sys/block/path_device/device/rescan 
    Ensure that you run this command for each of the path devices. For example, if your path devices are sda, sdb, sde, and sdf, you would run the following commands:
    # echo 1 > /sys/block/sda/device/rescan
    # echo 1 > /sys/block/sdb/device/rescan
    # echo 1 > /sys/block/sde/device/rescan
    # echo 1 > /sys/block/sdf/device/rescan
  4. Resize your multipath device by executing the multipathd resize command:
    # multipathd resize map multipath_device
  5. Resize the file system (assuming no LVM or DOS partitions are used):
    # resize2fs /dev/mapper/mpatha