Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions

  




 

 

NOTE: CentOS Enterprise Linux 5 is built from the Red Hat Enterprise Linux source code. Other than logo and name changes CentOS Enterprise Linux 5 is compatible with the equivalent Red Hat version. This document applies equally to both Red Hat and CentOS Enterprise Linux 5.

5.3. 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.

5.3.1. Reducing Swap on an LVM2 Logical Volume

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

  1. Disable swapping for the associated logical volume:

    # swapoff -v /dev/VolGroup00/LogVol01
    
  2. Reduce the LVM2 logical volume by 512 MB:

    # lvm lvreduce /dev/VolGroup00/LogVol01 -L -512M
    
  3. Format the new swap space:

    # mkswap /dev/VolGroup00/LogVol01
    
  4. Enable the extended logical volume:

    # swapon -va
    
  5. Test that the logical volume has been reduced properly:

    # cat /proc/swaps # free
    

5.3.2. Removing an LVM2 Logical Volume for Swap

The swap logical volume cannot be in use (no system locks or processes on the volume). The easiest way to achieve this it to boot your system in rescue mode. Refer to for instructions on booting into rescue mode. When prompted to mount the file system, select Skip.

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

  1. Disable swapping for the associated logical volume:

    # swapoff -v /dev/VolGroup00/LogVol02
    
  2. Remove the LVM2 logical volume of size 512 MB:

    # lvm lvremove /dev/VolGroup00/LogVol02
    
  3. Remove the following entry from the /etc/fstab file:

    /dev/VolGroup00/LogVol02   swap     swap    defaults     0 0
    
  4. Test that the logical volume has been extended properly:

    # cat /proc/swaps # free
    

5.3.3. Removing a Swap File

To remove a swap file:

  1. At a shell prompt as root, 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. Remove the actual file:

    # rm /swapfile
    

 
 
  Published under the terms of the GNU General Public License Design by Interspire