I've deleted my existing swap partition due to some partitioning problem. I don't have a swap space now so I've created a swap file with:
dd if=/dev/zero of=/root/myswapfile bs=1M count=1024 Here's after swapon -s:
/root/myswapfile file 1048572 1320 -1 Now I want to edit my /etc/fstab to enable the swap file after reboot.
1 Answer
These ares the steps to create a swap on a file:
Create a large file e.g. with
sudo mkdir -p /var/cache/swap/ # create a directory that holds the swap file sudo dd if=/dev/zero of=/var/cache/swap/myswap bs=1M count=4096 # for 4 GByte Of course any other method of creating a file of defined size would do.
Announce swap to the system
sudo chmod 0600 /var/cache/swap/myswap # only root should have access sudo mkswap /var/cache/swap/myswap # format as swap sudo swapon /var/cache/swap/myswap # announce to system Insert the following line in /etc/fstab for swap from the next boot:
/var/cache/swap/myswap none swap sw 0 0 Note: In case you have your system files on a SSD you may want to consider to hold your swap file on a hard disk location.
Also note: You can not use a swap file for hibernation (see Ubuntu SwapFaq)
Additional note for Ubuntu >= 17.04: A swap on file /swapfile is created by default in a new installation (when no swap partition was present). We can manually create a swap partition later if we prefer.
In case we want to replace an existing swap (e.g. partition) with another swap (e.g. on file) we need to remove the old swap with
sudo swapoff -a # for all Then remove the swap entry from /etc/fstab or replace it with the new swap respectively.
