On Fri, Nov 13, 2020 at 05:44:57PM +0000, Patrick O'Callaghan wrote: > > It's been years since I did this so things may have changed (I don't > use hibernation as it doesn't work with GPU passthrough for VMs), but > in my notes it says to add the UUID of the swap device to the command > line in /etc/sysconfig/grub: > > GRUB_CMDLINE_LINUX="... resume=UUID=xxxxxxxxxxxxxxxx ..." > > and then run 'grub2-mkconfig' to do its magic. I'm not sure if this can > be adapted to using a swapfile, but something tells me it can't. It has > to be a device or partition unless things have changed. I'm sure more > experienced hands will correct this if I'm wrong. There are extra steps if you use a swap file, instead of a swap partition. According to the kernel documentation: https://www.kernel.org/doc/html/latest/power/swsusp-and-swap-files.html The Linux kernel handles swap files almost in the same way as it handles swap partitions and there are only two differences between these two types of swap areas: (1) swap files need not be contiguous, (2) the header of a swap file is not in the first block of the partition that holds it. From the swsusp’s point of view (1) is not a problem, because it is already taken care of by the swap-handling code, but (2) has to be taken into consideration. In principle the location of a swap file’s header may be determined with the help of appropriate filesystem driver. Unfortunately, however, it requires the filesystem holding the swap file to be mounted, and if this filesystem is journaled, it cannot be mounted during resume from disk. For this reason to identify a swap file swsusp uses the name of the partition that holds the file and the offset from the beginning of the partition at which the swap file’s header is located. For convenience, this offset is expressed in <PAGE_SIZE> units. In order to use a swap file with swsusp, you need to: 1) Create the swap file and make it active, eg.: # dd if=/dev/zero of=<swap_file_path> bs=1024 count=<swap_file_size_in_k> # mkswap <swap_file_path> # swapon <swap_file_path> 2) Use an application that will bmap the swap file with the help of the FIBMAP ioctl and determine the location of the file’s swap header, as the offset, in <PAGE_SIZE> units, from the beginning of the partition which holds the swap file. 3) Add the following parameters to the kernel command line: resume=<swap_file_partition> resume_offset=<swap_file_offset> where <swap_file_partition> is the partition on which the swap file is located and <swap_file_offset> is the offset of the swap header determined by the application in 2) (of course, this step may be carried out automatically by the same application that determines the swap file’s header offset using the FIBMAP ioctl) -- Jonathan Billings <billings@xxxxxxxxxx> _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
