Configuration Swap

Swap Configuration

Swap space configuration for Ubuntu 16.04

• Check available swap

sudo swapon --show
sudo free -h

• Check space available

sudo df -h

• Create swap file

sudo fallocate -l [size_in_giga] /swapfile
-------
sudo fallocate -l 8.0G /swapfile    # set 8GByte
ls -lh /swapfile                    # verify swap

• Enabling swap file

sudo chmod 600 /swapfile
ls -lh /swapfile                    # verify permission

• Marked swap file

sudo mkswap /swapfile
-------
Setting up swapspace version 1, size = 8 GiB (8589930496 bytes)
no label, UUID=267498be-04b8-48d0-bf67-e43f18d03e49

• Allow system to start

sudo swapon /swapfile

Test & Validation

• Verify swap available

sudo swapon --show
-------
NAME      TYPE SIZE USED PRIO
/swapfile file   8G   0B   -1

• Check output free

free -h

Setup /etc/fstab Swap

• Backup old configuration /etc/fstab

sudo cp /etc/fstab /etc/fstab.bak

• Add swap file information

echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

• Adjusting the Cache Pressure Setting

sudo sysctl vm.vfs_cache_pressure=50
sudo sysctl vm.swappiness=10

• Edit configration /etc/sysctl.conf, add in bottom line:

vm.swappiness=10
vm.vfs_cache_pressure=50

• Remounting all partition & swap

sudo mount -a

• View free memory

sudo free -m
-------
              total        used        free      shared  buff/cache   available
Mem:          16046         139       15152          20         753       15568
Swap:         32767           0       32767

sudo free -h
-------
Mem:            15G        141M         14G         20M        754M         15G
Swap:           31G          0B         31G

Notes

• References: Digital Ocean - Swap