Jul 23, 2020 · Activation needs to be done by com‐ mand swapon(8). See also command btrfs inspect-internal map-swapfile and the Swapfile feature de‐ scription. NOTE: The command is a simplified version of 'mkswap', if you want to set label, page size, or other parameters please use 'mkswap' proper.

swapon --show. This is a bit better than swapon -s as it provides human friendly size units. E.g. if swap is active you could see: NAME TYPE SIZE USED PRIO /dev/dm-1 partition 7.5G 563.8M -2 If swap is not active, it doesn't show anything. man swap says:-s, --summary

Jul 21, 2016 · @Masi swapon creates swap memory that is available for all applications system-wide. The applications do not need to run as root to use it. The applications do not need to run as root to use it. – John1024

Aug 6, 2016 · @DanielWisehart swapon doesn't need the zeros. swapon needs the physical space to actually be there already, and not just reserved for future use. You could even fill your swap file with /dev/random and it would still work (but slow to create the swap file).

Dec 31, 2017 · Setting up swapspace version 1, size = 100 MiB (104853504 bytes) no label, UUID=bde6a47d-47f9-46b8-a492-786ab9565813 [root@localhost ~]# chmod 600 /tmp/swapfile [root@localhost ~]# swapon /tmp/swapfile swapon: /tmp/swapfile: swapon failed: Invalid argument Then map the swapfile to a loopback device and swapon.

Dec 6, 2014 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Oct 7, 2020 · While seeing the manual for swapon command the priorty option is described as-p, --priority priority Specify the priority of the swap device. priority is a value between -1 and 32767. Higher numbers indicate higher priority. See swapon(2) for a full description of swap priorities.

Jul 22, 2011 · swapon have -p switch which sets the priority. I can set up: swapon -p 32767 /dev/zram0 swapon -p 0 /dev/my-lvm-volume/swap Or in /etc/fstab: /dev/zram0 none swap sw,pri=32767 0 0 /dev/my-lvm-volume/swap none swap sw,pri=0 0 0 EDIT: Just for a full solution - such line may be helpful as udev rule:

Jul 26, 2021 · These files will be rejected by swapon. Preallocated files created by fallocate may be interpreted as files with holes too depending on the filesystem. Preallocated swap files are supported on XFS since Linux 4.18. The most portable solution to create a swap file is to use dd and /dev/zero. (Source: swapon manpage)

I'm assuming this means it worked fine. I've chmodded the file to 0600, and the file is owned by root. I then ran swapon: $ swapon -v /swap/sw1 swapon on /swap/sw1 swapon: /swap/sw1: Operation not permitted I've also tried adding this to fstab and calling swapon -a -v, but go the same problem. Why am I not allowed to use this file as a swap file?