Add Swap File to Ubuntu VM

Mindwatering Incorporated

Author: Tripp W Black

Created: 10/29 at 12:24 AM

 

Category:
Ubuntu
Configuration Files

Task:
VM has no swap. Would like to add a swap file.


Steps:
1. Become root:
$ sudo su -
<enter password>

2. Verify VM memory and if has a swap:
# free -h
total used free shared buff/cache available
Mem: 7.7Gi 5.8Gi 102Mi 299Mi 2.4Gi 2.0Gi

Note:
If you see a Swap entry like below, then the server already has one - either a partition or a file.
Check the /etc/fstab for the existing swap config.
e.g.
Swap: 4.0Gi 0B 4.0Gi


3. If there was a swap file, and not partition, and you wanted to change it, turn it off with:
# swapoff -a

Note:
Ensure beforehand that you have the physical memory to transfer any used swap to physical memory.

4. Create the empty swapfile and set its permissions for system access:
# dd if=/dev/zero of=/swapfile bs=1M count=4096
<wait a few seconds, the bigger the swap file, the longer to wait>

# chmod 0600 /swapfile

5. Initialize the swapfile and enable it:
# mkswap /swapfile
# swapon /swapfile

5. Confirm the swapfile is working:
# free -h
total used free shared buff/cache available
Mem: 7.7Gi 5.8Gi 102Mi 299Mi 2.4Gi 2.0Gi
Swap: 4.0Gi 0B 4.0Gi

6. If swap is listed, it is working. Add the swapfile to the end of the boot /etc/fstab config:
# vi /etc/fstab
...
/swapfile none swap sw 0 0

<esc>:wq (to save)


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