I'm running Ubuntu 20.04, and I'm trying to create a hibernate command. I'm following these instructions.
Step 2 says
Then check whether the swap memory you allocated is more than or at least equal to the Physical memory(RAM).
I did that, and my /swapfile is 2 GB. I have 16 GB RAM, so I need to increase the size of that swap file. How do I do that in Ubuntu?
In sleep mode, the content of ram is kept as it is, and the computer works on a very low power mode, so as to keep the ram content intact (as ram will lose the data if power supply is cut to it). But in hibernation, the ram content is stored in the swap space, so power can be completely cut off. Hence it is recommended to have swap size as large as the ram size.
First, find the swap file, disable and delete it
swapon --show
NAME TYPE SIZE USED PRIO
/swapfile file 2G 0B -2
sudo swapoff /swapfile
sudo rm /swapfile
Create new swap space of size 16 GB (16 * 1024 = 16384). bs is the block size. Basically bs * count = bytes to be allocated (in this case 16 GB). Here bs = 1M (M stands for mega, so we are assigning 1MB block size) and we are allocating 16384 * 1MB (=16GB) to swap.
sudo dd if=/dev/zero of=/swapfile bs=1M count=16384
Give it the read/write permission for root
sudo chmod 600 /swapfile
Format it to swap
sudo mkswap /swapfile
Turn on swap again
sudo swapon /swapfile
Now reboot the PC for the above changes to take place.
Below steps worked for me with fallocate approach
sudo swapon --show
Output will be something like below,
NAME TYPE SIZE USED PRIO
/swapfile file 2G 0G -2
sudo swapoff /swapfile
fallocate to instantly creates a file with the specified size.
sudo fallocate -l 16G /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
sudo swapon --show
Now the output will be something like below,
NAME TYPE SIZE USED PRIO
/swapfile file 16G 0B -2
Cheers!
sudo su -
swapoff /swapfile
rm /swapfile
\# 32k -> 32GB swap size
dd if=/dev/zero of=/swapfile bs=1M count=32K
mkswap /swapfile
swapon /swapfile
Ctrl+D
