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koub
Asked: 2021-03-05 05:38:12 +0800 CST

Ubuntu not recognizing all swap space

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I have issue regarding my swap size.

When I issue htop I get this output showing that I only have 2 GB of swap space:

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Also when I check system monitor:

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But, If I check the swap partition using Gparted, it is showing that I have 21 GB of swap space:

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Also the output of swapon -s is:

Filename                Type        Size    Used    Priority
/swapfile                               file        2097148 0   -2

Why Ubuntu isn't using all available swap space and just using 2GB?

dual-boot

2 Answers

  1. Best Answer

    The problem is that you haven't properly set up your /etc/fstab.

    There are two kinds of swap available to you. A /swapfile, or a partition-based swap area. You have to decide on one or the other.

    Note: A 22G swap partition is excessive (unless you're planning on hibernating).

    Your /etc/fstab currently has something like:

    /swapfile  none  swap  sw  0  0

    You should either increase your 2G /swapfile to 4G, or switch your swap line to use your /dev/sda7 swap partition, with something like:

    UUID=071f8b0e-8e16-4f4d-90ff-a4ae9cc56e2b  none  swap       sw       0       0

    Note: changing the UUID to what's found in the sudo blkid command.

    To increase your current /swapfile to 4G, do the following:

    Note: Incorrect use of the dd command can cause data loss. Suggest copy/paste.

    In the terminal...

    sudo swapoff -a           # turn off swap
sudo rm -i /swapfile      # remove old /swapfile

sudo dd if=/dev/zero of=/swapfile bs=1M count=4096

sudo chmod 600 /swapfile  # set proper file protections
sudo mkswap /swapfile     # init /swapfile
sudo swapon /swapfile     # turn on swap
free -h                   # confirm 16G RAM and 4G swap

    Confirm this /swapfile line at the end of /etc/fstab... and confirm no other “swap” lines...

    To edit, use sudo -H gedit /etc/fstab or sudo pico /etc/fstab

    /swapfile  none  swap  sw  0  0

    reboot                    # reboot and verify operation

    Note: Then you can remove your 22G swap partition /dev/sda7.

    • 2

  2. swapon -s indicates the swap space that is currently in use. The output of your command indicates that a swapfile, /swapfile, is in use. Your swap partition is not used. For it to be used, it would need to be included into /etc/fstab. Currently, you will see an entry for /swapfile. You would need to add another entry for the swap partition.

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