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
- Disable swapping for the associated logical volume:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow swapoff -v /dev/VolGroup00/LogVol01
# swapoff -v /dev/VolGroup00/LogVol01
- Reduce the LVM2 logical volume by 512 MB:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow lvreduce /dev/VolGroup00/LogVol01 -L -512M
# lvreduce /dev/VolGroup00/LogVol01 -L -512M
- Format the new swap space:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow mkswap /dev/VolGroup00/LogVol01
# mkswap /dev/VolGroup00/LogVol01
- Activate swap on the logical volume:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow swapon -v /dev/VolGroup00/LogVol01
# swapon -v /dev/VolGroup00/LogVol01
- To test if the swap logical volume was successfully reduced, inspect active swap space:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow cat /proc/swaps free -h
$ 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
- Disable swapping for the associated logical volume:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow swapoff -v /dev/VolGroup00/LogVol02
# swapoff -v /dev/VolGroup00/LogVol02
- Remove the LVM2 logical volume:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow lvremove /dev/VolGroup00/LogVol02
# lvremove /dev/VolGroup00/LogVol02
- Remove the following associated entry from the
/etc/fstab
file:Copy to Clipboard Copied! Toggle word wrap Toggle overflow /dev/VolGroup00/LogVol02 swap swap defaults 0 0
/dev/VolGroup00/LogVol02 swap swap defaults 0 0
- Regenerate mount units so that your system registers the new configuration:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow systemctl daemon-reload
# systemctl daemon-reload
- Remove all references to the removed swap storage from the
/etc/default/grub
file:Copy to Clipboard Copied! Toggle word wrap Toggle overflow vi /etc/default/grub
# vi /etc/default/grub
- Rebuild the grub configuration:
- on BIOS-based machines, run:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow grub2-mkconfig -o /boot/grub2/grub.cfg
# grub2-mkconfig -o /boot/grub2/grub.cfg
- on UEFI-based machines, run:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
- To test if the logical volume was successfully removed, inspect active swap space:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow cat /proc/swaps free -h
$ cat /proc/swaps $ free -h
15.2.3. Removing a Swap File
To remove a swap file:
Procedure 15.5. Remove a Swap File
- At a shell prompt, execute the following command to disable the swap file (where
/swapfile
is the swap file):Copy to Clipboard Copied! Toggle word wrap Toggle overflow swapoff -v /swapfile
# swapoff -v /swapfile
- Remove its entry from the
/etc/fstab
file. - Regenerate mount units so that your system registers the new configuration:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow systemctl daemon-reload
# systemctl daemon-reload
- Remove the actual file:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow rm /swapfile
# rm /swapfile