Re: Adding file swap on btrfs

On Mon, Dec 19, 2022 at 2:10 PM Samuel Sieb <samuel(a)sieb.net <mailto:samuel@sieb.net>> wrote: On 12/19/22 11:58, Neal Becker wrote: > I've just installed f37 on a new lenovo x1 carbon. > One thing, the installation didn't setup any swap (other than zswap). > > After a bit of reading I found > sudo btrfs filesystem mkswapfile -s 32G /swapfile > But: >   sudo swapon -v /swapfile > swapon: /swapfile: found signature [pagesize=4096, signature=swap] > swapon: /swapfile: pagesize=4096, swapsize=1073741824, devsize=34359738368 > > Although I created 32G swapfile, only 1G is used. > swapon > NAME       TYPE       SIZE USED PRIO > /dev/zram0 partition    8G 6.3M  100 > /swapfile  file      1024M   0B   -2 > > > What's wrong? Something is wrong with how it creates the swap format.  Just run "mkswap /swapfile" and it will be fine. Not quite, without the chattr +C it will still perform COW file operations which you don't want on large files.