zram.sh

#!/usr/bin/bash

## Watch This Space || full write-up, accompanying explainer doc coming soon

###	zram kernel optimizations
##	https://github.com/garyexplains/examples/blob/master/how_to_enable_ZRAM_Raspberry_Pi.md#kernel-parameters-to-make-better-use-of-zram
cat << 'EOF' | sudo tee /etc/sysctl.d/99-vm-zram-parameters.conf
vm.vfs_cache_pressure=500
vm.swappiness=100
vm.dirty_background_ratio=1
vm.dirty_ratio=50
vm.watermark_boost_factor = 0
vm.watermark_scale_factor = 125
vm.page-cluster = 0
EOF


###	zram-tools, or ez-mode
sudo apt install -y zram-tools

sudo sed -i -e 's/#PERCENT=50/PERCENT=175/' /etc/default/zramswap
##	https://github.com/NixOS/nixpkgs/pull/351002#issuecomment-2563183156
## NOTE __ ram usage percentage : 150 seems on the lower end
## TUDO :: revisit w/ hard data

#sudo sed -i -e 's/#ALGO=lz4/ALGO=zstd/' /etc/default/zramswap
## NOTE __ zstd > lz4 is workload dependant
## TUDO :: revisit w/ hard data



###
###	COMING SOON -- systemd/zram-generator, or hard mode
###

# sudo apt install -y systemd-zram-generator

## LINKS
##	https://wiki.archlinux.org/title/Zram#Using_zram-generator
##	https://github.com/systemd/zram-generator/blob/main/zram-generator.conf.example
## -- lesser misc links, unsorted, to get to
##   google  zram recompress huge idle huge_idle
##    https://github.com/systemd/zram-generator/issues/164
##    https://github.com/ValveSoftware/SteamOS/issues/899
##    https://www.reddit.com/r/Ubuntu/comments/1dduz30/how_to_increase_zram_compression/

## TUDO :: write a few sed's to convert defaults into optimized
## 	--	sudo sed -i -e 's/before/after/' /etc/systemd/zram-generator.conf
##	1.	zram-size = ram * 2
##	 https://github.com/NixOS/nixpkgs/pull/351002#issuecomment-2563183156
##	2.	compression-algorithm = lz4
##	2a	compression-algorithm = lz4 zstd(level=9)
##	 https://docs.kernel.org/admin-guide/blockdev/zram.html#recompression
##		note: recompression without optimized parameters ~= regressions
## OPTIONAL / AT A LATER DATE
##	3. replace swap with zram writeback
##	 https://docs.kernel.org/admin-guide/blockdev/zram.html#writeback
##	 : ditto above regression sentiment
##	4. swap-priority