Sometimes it is necessary to add more swap space after installation. For example, you may upgrade the amount of RAM in your system from 128 MB to 256 MB, but there is only 256 MB of swap space. It might be advantageous to increase the amount of swap space to 512 MB if you perform memory-intense operations or run applications that require a large amount of memory.
You have three options: create a new swap partition, create a new swap file, or extend swap on an existing LVM2 logical volume. It is recommended that you extend an existing logical volume.

7.2.1. Extending Swap on an LVM2 Logical Volume

To extend 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. Resize the LVM2 logical volume by 256 MB:
    lvm lvresize /dev/VolGroup00/LogVol01 -L +256M
  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 extended properly:
    cat /proc/swaps

7.2.2. Creating an LVM2 Logical Volume for Swap

To add a swap volume group (assuming /dev/VolGroup00/LogVol02 is the swap volume you want to add):
  1. Create the LVM2 logical volume of size 256 MB:
    lvm lvcreate VolGroup00 -n LogVol02 -L 256M
  2. Format the new swap space:
    mkswap /dev/VolGroup00/LogVol02
  3. Add the following entry to the /etc/fstab file:
    /dev/VolGroup00/LogVol02   swap     swap    defaults     0 0
  4. Enable the extended logical volume:
    swapon -va
  5. Test that the logical volume has been extended properly:
    cat /proc/swaps

7.2.3. Creating a Swap File

To add a swap file:
  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. Change the persmissions of the newly created file:
    chmod 0600 /swapfile
  4. Setup the swap file with the command:
    mkswap /swapfile
  5. To enable the swap file immediately but not automatically at boot time:
    swapon /swapfile
  6. 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.
  7. After adding the new swap file and enabling it, verify it is enabled by viewing the output of the command cat /proc/swaps or free.
0 (0)
Article Rating (No Votes)
Rate this article
There are no attachments for this article.
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
RHCS6: Create a new Logical Volume / Global Filesystem 2 (GFS2)
Viewed 905 times since Sun, Jun 3, 2018
stunnel: Authentication
Viewed 816 times since Fri, Sep 28, 2018
How To: Create Self-Signed Certificate – OpenSSL
Viewed 729 times since Mon, Feb 18, 2019
Modifying the inode count for an ext2/ext3/ext4 file system
Viewed 390 times since Fri, Sep 18, 2020
20 Linux YUM (Yellowdog Updater, Modified) Commands for Package Management YUM
Viewed 9456 times since Thu, Oct 25, 2018
RHEL: Resize/disable /dev/shm filesystem
Viewed 4299 times since Sun, May 27, 2018
How To Find Largest Top 10 Files and Directories On Linux / UNIX / BSD find
Viewed 657 times since Mon, Oct 29, 2018
RHCS6: Mirror/unmirror a GFS2 volume
Viewed 895 times since Sun, Jun 3, 2018
Logowanie za pomocą kluczy Secure Shell
Viewed 1314 times since Thu, May 24, 2018
Viewed 1023 times since Sat, Jun 2, 2018