Managing swap files and partitions may be a necessary system administration task, if our system ever runs low on memory. In this activity, we will be creating a swap partition and a swap file. We will also be looking at activating and deactivating swap space, viewing swap usage, and making swap space available persistently. At the conclusion, we will understand how to work with swap files and partitions when needed to augment system memory.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Create a Persistent 1 GB Swap Partition
Using
fdisk
, create the swap partition:sudo -i fdisk /dev/xvdg
Press the following to create the partition:
- n for new partition
- Enter to select the default (primary) type
- Enter for the default first sector
- +1G for the size of the partition
- t to change the type
- L to list the types
- 82 for Linux Swap
- w to write changes and quit
Execute
mkswap
to format the partition:mkswap /dev/xvdg1
Add an entry to
/etc/fstab
:/dev/xvdg1 none swap defaults 0 0
Verify swap partition is activated:
swapon -s swapon -a swapon -s
- Create a Persistent 512 MB Swap File
Use the
dd
command to create a 512 MB/root/extra.swp
file:dd if=/dev/zero of=/root/extra.swp bs=1M count=512
Format and activate the
/root/extra.swap
by executingmkswap
:mkswap /root/extra.swp swapon /root/extra.swp
Set more secure 0600 permissions using the
chmod
command:chmod 0600 /root/extra.swp ls -l /root/extra.swp
Add an entry to
/etc/fstab
to activate the swap file:/root/extra.swp none swap defaults 0 0
Activate the swap file entry:
swapoff /root/extra.swp swapon -a swapon -s