5.4. Moving swap File Systems from a Single Path Device to a Multipath Device

By default, swap devices are set up as logical volumes. This does not require any special procedure for configuring them as multipath devices as long as you set up multipathing on the physical volumes that constitute the logical volume group. If your swap device is not an LVM volume, however, and it is mounted by device name, you may need to edit the fstab file to switch to the appropriate multipath device name.
  1. Determine the WWID number of the swap device by running the /sbin/multipath command with the -v3 option. The output from the command should show the swap device in the paths list.
    You should look in the command output for a line of the following format, showing the swap device:
    WWID  H:B:T:L devname MAJOR:MINOR
    For example, if your swap file system is set up on sda or one of its partitions, you would see a line in the output such as the following:
    ===== paths list =====
    ...
    1ATA     WDC WD800JD-75MSA3                           WD-WMAM9F 1:0:0:0 sda 8:0
    ...
    
  2. Set up an alias for the swap device in the /etc/multipath.conf file:
    multipaths {
        multipath {
            wwid WWID_of_swap_device
            alias swapdev
        }
    }
    
  3. Edit the /etc/fstab and replace the old device path to the root device with the multipath device.
    For example, if you had the following entry in the /etc/fstab file:
    /dev/sda2 swap                    swap    defaults        0 0
    
    You would change the entry to the following:
    /dev/mapper/swapdev swap          swap    defaults        0 0