Python rewrite

Major changes

• systemd-swap is now completely rewritten in python
• systemd-swap compression lists available compression algorithms (#93)

Minor changes

• systemd-swap status now works without root (some info requires root and are not displayed without sudo)
• systemd-swap can now swapon virtblk disks (for use within VMs)

New dependencies

• python-sysv-ipc
• python-systemd
• >=python-3.7

The last(?) bash release, next release on python

This is a simple release containing the last fixups of the bash code before moving on to the python rewrite (#164), if there are requests to continue the bash version a 4.3.x branch will be created and maintained for the foreseeable future.

Fixes

• Properly set swapd_prio (#169)
• Fix a error message on some Debian based systems when building the package (#168)

Properly handle loading of zram module

4.3.1 did not actually fix this issue

Zram, BTRFS and loopback regression fixes

• Allow for loopback devices once again (however if you need to use loopback please report why)
• Use dd for all filesystems, fixing #155 when using swapFC on BTRFS
• Fix a issue where the zram module would not load properly on startup causing all kinds of problems
• (Debian based distros) don't override configuration files in /etc

All around updates

• Properly create btrfs subvolume introduced in 4.2.2
• New variable swapfc_free_ram_perc for setting the first swapfc file (other swapfc swap files are still managed by swapfc_free_swap_perc)
• Some performance improvements by rewriting external programs in pure bash code

Small regression fixes

• Set swapfc_priority to 50 by default so that systemd doesn't log warning (#135)
• Check if swapfc_frequency is a valid integer, error otherwise (#121)

More regression fixes

• Now allows swapon for swap partitions found on /dev/sd* and /dev/nvme*.
• Now always swapon all zram devices (previously the first one would under certain circumstances not be made active).
• Create a btrfs subvolume in swapfc_path so that snapshots work.
• SwapFC now more accuratly logs why the swap file was created.

Fix zram regression

Last release carried a regression causing zrams size to be too large. (#134)

Restructuring of configuration files and man pages

New features

We now read configuration options from the following files and folders:

• /etc/systemd/swap.conf.d/*.conf
• /run/systemd/swap.conf.d/*.conf
• /usr/lib/systemd/swap.conf.d/*.conf
• /etc/systemd/swap.conf
• /usr/share/systemd-swap/swap-default.conf
  (With priority from top to bottom).

We now support some new configuration options:

• swapfc_remove_free_swap_perc Allows defining at what % of available ram we remove a swap file (defaluts to 55 which is the old value of swapfc_free_swap_perc + 40.
• swapfc_min_count Just how you can define the maximum number of swap files created by swapfc, you can now define a minimum that will always be allocated (for instanse to restore the old behaviour of creating a swap file on startup set this to 1). Defaults to 0.
• swapfc_priority Sets the priority of swap files created by swapfc (decreasing by one for every swap file created). Defaults to -2 (old default).

There are two new man pages, 5 swap.conf and 8 systemd-swap.

Please read through them and send in grammar mistakes and anything you would like to be added 🥳 .

Misc

• Further removal of use of external programs thus improving performance (thanks zenofile).
• Additional systemd hardening.
• Run as type=notify which should improve the output of systemctl status systemd-swap.
• Run systemd-swap at "realtime" priority (1ac16cb if you're interested).
• Code refactoring and cleanup.
• Log when we start creating swap files and warn if combining zram with zswap/swapfc/swapd.
• Never shred the swap file before using it (previously it would shred if the filesystem was not ext* or btrfs) (3f2e5a9 & 41d86af).

BTRFS swapfile support and code cleanup

New features

• BTRFS swapfile support
• Only create the first swapfile (swapfc) if we're low on ram instead of on startup
• Setting to specify zRAM count

Updates

• Update defaults to zstd compression and z3fold
• Remove dependencies on external shell programs improving performance
• Various code cleanups
• Various documentation updates
• Harden systemd service

Bug fixes

• Use dd instead of fallocate if we're on ext4/3, f2fs or xfs (#109)
• Don't attempt chattr +C on filesystems that don't support the flag

Regressions

If you're running Ubuntu 18.04 or Centos 7 or older, please comment out line 25 in /usr/lib/systemd/system/systemd-swap.service (see #118)