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15.2. Removing Swap Space

Sometimes it can be prudent to reduce swap space after installation. For example, you have downgraded the amount of RAM in your system from 1 GB to 512 MB, but there is 2 GB of swap space still assigned. It might be advantageous to reduce the amount of swap space to 1 GB, since the larger 2 GB could be wasting disk space.
You have three options: remove an entire LVM2 logical volume used for swap, remove a swap file, or reduce swap space on an existing LVM2 logical volume.

15.2.1. Reducing Swap on an LVM2 Logical Volume

To reduce an LVM2 swap logical volume (assuming /dev/VolGroup00/LogVol01 is the volume you want to reduce):

Procedure 15.3. Reducing an LVM2 Swap Logical Volume

  1. Disable swapping for the associated logical volume: 
    # swapoff -v /dev/VolGroup00/LogVol01
  2. Reduce the LVM2 logical volume by 512 MB: 
    # lvreduce /dev/VolGroup00/LogVol01 -L -512M
  3. Format the new swap space: 
    # mkswap /dev/VolGroup00/LogVol01
  4. Activate swap on the logical volume: 
    # swapon -v /dev/VolGroup00/LogVol01
  5. To test if the swap logical volume was successfully reduced, inspect active swap space: 
    $ cat /proc/swaps
$ free -h

15.2.2. Removing an LVM2 Logical Volume for Swap

To remove a swap volume group (assuming /dev/VolGroup00/LogVol02 is the swap volume you want to remove):

Procedure 15.4. Remove a Swap Volume Group

  1. Disable swapping for the associated logical volume: 
    # swapoff -v /dev/VolGroup00/LogVol02
  2. Remove the LVM2 logical volume: 
    # lvremove /dev/VolGroup00/LogVol02
  3. Remove the following associated entry from the /etc/fstab file: 
    /dev/VolGroup00/LogVol02   swap     swap    defaults     0 0
  4. Regenerate mount units so that your system registers the new configuration: 
    # systemctl daemon-reload
  5. Remove all references to the removed swap storage from the /etc/default/grub file: 
    # vi /etc/default/grub
  6. Rebuild the grub configuration:
    1. on BIOS-based machines, run: 
      # grub2-mkconfig -o /boot/grub2/grub.cfg
    2. on UEFI-based machines, run: 
      # grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
  7. To test if the logical volume was successfully removed, inspect active swap space: 
    $ cat /proc/swaps
$ free -h

15.2.3. Removing a Swap File

To remove a swap file:

Procedure 15.5. Remove a Swap File

  1. At a shell prompt, execute the following command to disable the swap file (where /swapfile is the swap file): 
    # swapoff -v /swapfile
  2. Remove its entry from the /etc/fstab file.
  3. Regenerate mount units so that your system registers the new configuration: 
    # systemctl daemon-reload
  4. Remove the actual file: 
    # rm /swapfile