zram-swap
Simple zram swap setup + teardown script for modern systemd Linux systems
https://github.com/foundObjects/zram-swap
Why?
There are dozens of zram swap scripts out there, but most of them are overly complicated and do things that haven't been neccessary since linux 3.X or have massive logic errors in their swap size calculations. This script is simple and reliable, modern and easy to configure.
Installation
git clone https://github.com/foundObjects/zram-swap.git
cd zram-swap && sudo ./install.sh
Usage
zram-swap.service will be started automatically after installation and during each subsequent boot. The default allocation creates a zram device that should use around half of physical memory when completely full.
The default configuration using lz4 should work well for most people. lzo may provide slightly better RAM utilization at a cost of slightly more expensive decompression. zstd should provide better compression than lz* and still be moderately fast on most machines. On very modern kernels the best overall choice is probably lzo-rle.
Edit /etc/default/zram-swap if you'd like to change compression algorithms or
swap allocation and then restart zram-swap with systemctl restart zram-swap.service.
Run zramctl during use to monitor swap compression and real memory usage.
Debugging
Start zram-swap.sh with zram-swap.sh -x (start|stop) to view the debug trace
and determine what's going wrong.
To dump the full execution trace during service start/stop edit
/etc/systemd/systemd/zram-swap.service and add -x to the following two lines:
ExecStart=/usr/local/sbin/zram-swap.sh -x init
ExecStop=/usr/local/sbin/zram-swap.sh -x end
Compatibility
This should run on pretty much any recent (4.0+? kernel) Linux system using systemd. If anyone wants to try it on something really old and let me know how far back compatibility goes I'm interested, but I don't have any legacy systems to test on at the moment.
The script will also work on non-systemd Linux without issue and I welcome PRs supporting SysVinit.