One of problems I came across was that I didn't have partition for swap. In modern day, if you have enough RAM, swap partition is not necessary but it is required if you want to use suspend-to-disk. I found out that I could make swap file that will work same as swap partition.
You will need root access:
sudo -s
Now create actual file
dd if=/dev/zero of=/swapfile bs=1M count=2048
This command will create file named swapfile with size of 2GB (1MB x 2048). You can adjust these numbers to fit your needs.
Let's close huge local vulnerability but giving only root rights to read and write to the file with
chown root:root /swapfile
chmod 0600 /swapfile
After file is created type this command to make it swap
mkswap /swapfile
And to activate swap file
swapon /swapfile
To make your system activate this file after reboot, open /etc/fstab file with
vi /etc/fstab
And insert this line (adjust name of your file accordingly)
/swapfile none swap 0 0
To check if your file is active or not, type
free -m
You will need root access:
sudo -s
Now create actual file
dd if=/dev/zero of=/swapfile bs=1M count=2048
This command will create file named swapfile with size of 2GB (1MB x 2048). You can adjust these numbers to fit your needs.
Let's close huge local vulnerability but giving only root rights to read and write to the file with
chown root:root /swapfile
chmod 0600 /swapfile
After file is created type this command to make it swap
mkswap /swapfile
And to activate swap file
swapon /swapfile
To make your system activate this file after reboot, open /etc/fstab file with
vi /etc/fstab
And insert this line (adjust name of your file accordingly)
/swapfile none swap 0 0
To check if your file is active or not, type
free -m
Removing Swap file or partition
First find your swap partition with
sudo fdisk -l
And look for Linux Swap file. This is sample output
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 206847 204800 100M 7 HPFS/NTFS/exFAT
/dev/sda2 206848 164339711 164132864 78.3G 7 HPFS/NTFS/exFAT
/dev/sda3 164339712 564938406 400598695 191G 7 HPFS/NTFS/exFAT
/dev/sda4 564938750 625139711 60200962 28.7G 5 Extended
/dev/sda5 564938752 621996031 57057280 27.2G 83 Linux
/dev/sda6 621998080 625139711 3141632 1.5G 82 Linux swap / Solaris
In my case, swap partitions is /dev/sda6, to disable swap on this partition I type
swapoff /dev/sda6
Now go to /etc/fstab and comment out line with swap. This is that line in my fstab file:
UUID=9f0f62d3-44fd-4286-9b90-1faff3b4a44c swap swap defaults 0 0
To comment it, just add # on the beginning of the line. After rebooting, using free -m you could check that your swap is not there anymore (or if you had more than 1 swap partition/file it is reduced).
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