How to Add Swap Memory in Ubuntu 22.04
Swap memory is extra storage used when your server's RAM is full. It moves less active processes from RAM to a reserved space on disk, freeing up memory and preventing system crashes.
In this article, you are to add swap memory on Ubuntu 22.04. You are to use a block storage to increase the available server memory.
Prerequisites
Before you begin:
Have an Ubuntu 22.04 server.
Have an existing block storage.
Access the server using SSH as a non-root user with sudo privileges.
View Existing Swap Memory
Follow the steps in this section to view the already available swap memory on Ubuntu 22.04.
View the available server memory including RAM and Swap using the free utility.
CONSOLE
Verify the Swap memory available on your server similar to the output below.
Create Swap Memory
Follow the sections below to create swap memory using either a Swapfile or a dedicated block storage volume on your server.
Create Swap Memory using a Swapfile
Create a new Swapfile with a specific size such as
2GBusing thefallocateutility in your root directory/.CONSOLEModify the Swapfile permissions to allow only the root user to read and write changes on the file.
CONSOLEFormat the file as swap using
mkswap.CONSOLEVerify the new swap memory size, label information and UUID similar to the following output.
Create Swap Memory Using block storage
Vultr Block Storage is used here as an example to demonstrate the use of a dedicated block storage. You can replace the directories used in the commands to adjust according to any cloud provider.
List the storage devices available on your server using the
lsblkutility. The new disk is attached as/dev/vdband it has no partitions.CONSOLEOutput:
The Vultr Block Storage device is attached as
vdbbased on the above output with a40GBsize.Initialize the volume using the GPT partition table.
CONSOLECreate a new partition using the entire block storage volume.
CONSOLEVerify that the new block storage partitiion is available.
CONSOLEOutput:
Convert the new block storage partition to swap.
CONSOLEVerify that the new swap partition is available.
CONSOLEOutput:
Note the swap partition
UUIDvalue to use when mounting the volume automatically at boot time.
Enable Swap Memory
Enable the Swapfile as swap memory using the
swaponutility.CONSOLEView the server swap memory and verify that the new Swapfile is active.
CONSOLEOutput:
Run the following command to enable the Vultr Block Storage swap partition as swap memory. Replace
/dev/vdb1with your actual partition path.CONSOLEView the server swap memory and verify that the swap partition is active.
CONSOLEOutput:
Configure the File System Table (fstab) to Enable Automatic Mounting
The File System Table (fstab) controls how file systems are mounted on a server. Follow the steps below to set up fstab so your swap memory volumes mount automatically at boot.
Backup the original
fstabconfiguration on your server.CONSOLEOpen the
fstabconfiguration file using a text editor such asnano.CONSOLEAdd the following Swapfile configuration at the end of the file.
INISave and close the file.
The above configuration enables automatic mounting using the
/swapfile.imgfile.swap: Specifies the file system type as swap.swap: Defines the mount point for the swap space.0: Disables automatic backups for the swap file system.0: Skips file system checks on the swap memory.
View your block devices information and copy the UUID of new
/dev/vdb1.CONSOLEOutput:
Add the block storage swap partition using its
UUIDvalue to enable automatic mounting on the volume.INIReplace
UUID=ca230c16-b5a4-44e6-b5a8-930bb1f33fcfwith your server block deviceUUID.After configuring automatic mounting, the server will now automatically mount and activate swap memory at boot.
Configure Swappiness
A swappiness value controls how the server manages memory usage between RAM and swap space. A lower value reduces swapping, while a higher value increases it based on the following ranges:
0: Avoids swapping unless absolutely necessary.1-49: Swaps infrequently, only when RAM is nearly full.50: Balances RAM usage and swapping.51-99: Swaps more aggressively as RAM fills up.100: Prioritizes swapping, frequently moving processes from RAM to swap.
Follow the steps below to configure the swappiness value on your server.
Run the following command to modify the
/etc/sysctl.confwith your swappiness value. Replace50with your desired swapping level.CONSOLEOutput:
Reload the
systctlconfiguration to apply the configuration changes.CONSOLE
Test the Swap Memory
View all available swap volumes on your server.
CONSOLEOutput:
Run the following command to activate all inactive swap volumes in your
/etc/fstabconfiguration.CONSOLEView your server memory and verify the amount of swap memory actively in use.
CONSOLEOutput:
Remove Swap Memory
Use the
swapoffutility with the Swapfile or partition path to disable on your server. For example, run the following command to disable the default Swapfile/swapfile.CONSOLEView the swap volumes on your server and verify that the default Swapfile is disabled.
CONSOLEOutput:
Conclusion
In this article, you added swap memory on an Ubuntu 22.04 server and enabled swapping by extending the default system memory. For more configuration options, run $ man swapon to view the swap commands manual.
0 Comments
Be the first to comment and share your perspective with the community.