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 Copy linkLink copied to clipboard!
Copy linkLink copied to clipboard!
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:
swapoff -v /dev/VolGroup00/LogVol01
# swapoff -v /dev/VolGroup00/LogVol01Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Reduce the LVM2 logical volume by 512 MB:
lvreduce /dev/VolGroup00/LogVol01 -L -512M
# lvreduce /dev/VolGroup00/LogVol01 -L -512MCopy to Clipboard Copied! Toggle word wrap Toggle overflow - Format the new swap space:
mkswap /dev/VolGroup00/LogVol01
# mkswap /dev/VolGroup00/LogVol01Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Activate swap on the logical volume:
swapon -v /dev/VolGroup00/LogVol01
# swapon -v /dev/VolGroup00/LogVol01Copy to Clipboard Copied! Toggle word wrap Toggle overflow - To test if the swap logical volume was successfully reduced, inspect active swap space:
cat /proc/swaps $ free -h
$ cat /proc/swaps $ free -hCopy to Clipboard Copied! Toggle word wrap Toggle overflow
15.2.2. Removing an LVM2 Logical Volume for Swap Copy linkLink copied to clipboard!
Copy linkLink copied to clipboard!
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:
swapoff -v /dev/VolGroup00/LogVol02
# swapoff -v /dev/VolGroup00/LogVol02Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Remove the LVM2 logical volume:
lvremove /dev/VolGroup00/LogVol02
# lvremove /dev/VolGroup00/LogVol02Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Remove the following associated entry from the
/etc/fstabfile:/dev/VolGroup00/LogVol02 swap swap defaults 0 0
/dev/VolGroup00/LogVol02 swap swap defaults 0 0Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Regenerate mount units so that your system registers the new configuration:
systemctl daemon-reload
# systemctl daemon-reloadCopy to Clipboard Copied! Toggle word wrap Toggle overflow - Remove all references to the removed swap storage from the
/etc/default/grubfile:vi /etc/default/grub
# vi /etc/default/grubCopy to Clipboard Copied! Toggle word wrap Toggle overflow - Rebuild the grub configuration:
- on BIOS-based machines, run:
grub2-mkconfig -o /boot/grub2/grub.cfg
# grub2-mkconfig -o /boot/grub2/grub.cfgCopy to Clipboard Copied! Toggle word wrap Toggle overflow - on UEFI-based machines, run:
grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfgCopy to Clipboard Copied! Toggle word wrap Toggle overflow
- To test if the logical volume was successfully removed, inspect active swap space:
cat /proc/swaps $ free -h
$ cat /proc/swaps $ free -hCopy to Clipboard Copied! Toggle word wrap Toggle overflow
15.2.3. Removing a Swap File Copy linkLink copied to clipboard!
Copy linkLink copied to clipboard!
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
/swapfileis the swap file):swapoff -v /swapfile
# swapoff -v /swapfileCopy to Clipboard Copied! Toggle word wrap Toggle overflow - Remove its entry from the
/etc/fstabfile. - Regenerate mount units so that your system registers the new configuration:
systemctl daemon-reload
# systemctl daemon-reloadCopy to Clipboard Copied! Toggle word wrap Toggle overflow - Remove the actual file:
rm /swapfile
# rm /swapfileCopy to Clipboard Copied! Toggle word wrap Toggle overflow