Installation guide

Removing Swap Space

1. Determine the size of the new swap file in megabytes and multiply by 1024 to determine the

number of blocks. For example, the block size of a 64 MB swap file is 65536.

2. At a shell prompt as root, type the following command with count being equal to the desired

block size:

dd if=/dev/zero of=/swapfile bs=1024 count=65536

3. Setup the swap file with the command:

mkswap /swapfile

4. To enable the swap file immediately but not automatically at boot time:

swapon /swapfile

5. To enable it at boot time, edit /etc/fstab to include the following entry:

/swapfile swap swap defaults 0 0

The next time the system boots, it enables the new swap file.

To test if the new swap file was successfully created, use cat /proc/swaps or free to inspect the

swap space.

14.3. Removing Swap Space

Sometimes it can be prudent to reduce swap space after installation. For example, say you

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.

14.3.1. 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):

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. Enable the extended logical volume:

swapon -v /dev/VolGroup00/LogVol01

To test if the swap's logical volume size was successfully reduced, use cat /proc/swaps or free

to inspect the swap space.