Script for creating hybrid swap space from zram swaps, swap files and swap partitions.
Clone or download

README.md

systemd-swap

Script for manage swap on:

  • zswap - Enable/Configure
  • zram - Autoconfigurating for swap
  • files - (sparse files for saving space, support btrfs)
  • block devices - auto find and do swapon

It is configurable in /etc/systemd/swap.conf.

Additional terms:

  • SwapFC (File Chunked) - provide a dynamic swap file allocation/deallocation

Files placed:

/etc/systemd/swap.conf
/usr/lib/systemd/system/systemd-swap.service
/usr/bin/systemd-swap

Please not forget to enable by:

# systemctl enable systemd-swap

Install

$ git clone https://github.com/Nefelim4ag/systemd-swap.git
$ ./systemd-swap/package.sh debian
$ sudo dpkg -i ././systemd-swap/systemd-swap-*any.deb
$ git clone https://github.com/Nefelim4ag/systemd-swap.git
$ ./systemd-swap/package.sh fedora f28
$ sudo dnf install ./systemd-swap/systemd-swap-*noarch.rpm
  • Manual
$ git clone https://github.com/Nefelim4ag/systemd-swap.git
$ sudo make install

About configuration

Q: WTF?! Why you merge swapFC and swapFU?
A: That simplify testing of swapFC code and make code more generic

Q: How can i migrate config swapFU from 3.X to 4.X?
A: Most of switches are same, to get configuration like swapFU from swapFC, set swapfc_max_count to 1 and swapfc_chunk_size to size of swapFU.

Q: Do we need to activate both zram and zswap?
A: Nope, it's useless, as zram is a compressed RAM DISK, but zswap is a compressed "writeback" CACHE on swap file/disk.

Q: Do i need use swapfc_force_use_loop on swapFC?
A: Nope, as you wish really, native swapfile must work faster and it's more safe in OOM condition in comparison to loop backed scenario.

Q: When would we want a certain configuration?
A: In most cases (Notebook, Desktop, Server) it's enough to enable zswap + swapfc (On server tuning of swapfc can be needed).
In case where SSD used, and you care about flash wear, use only ZRam.

Q: Where is the swap file located?
A: Read carefully swap.conf

Q: Can we use this to enable hibernation?
A: Nope as hibernation wants a persistent fs blocks and wants access to swap data directly from disk, this will not work on: zram, swapfu, swapfc (without some magic of course).

Note:

  • For zram support: Dependence: util-linux >= 2.26
  • If you use zram not for only swap, use kernel 4.2+ or please add rule for modprobe like:
options zram max_devices=32