What is random.bin? I was testing with a json dataset that compresses by factor like 2.5 with zram. But if random is incompressible, then zram does not write compressed data but rather the original resulting in much faster read speed.

Also on your SSD do you have logical 4K sector or 512 byte sectors? If the latter, then Linux distros defaults to 512 LUKS sectors on them resulting in much slower performance especially with writes.

I always ensure that LUKS sectors are 4K even if SSD reports 512 bytes and does not allow to change that to 4K like Samsung 9* series.

▲ vlovich123 a day ago | parent [-]

4k sectors. I don’t have a 25gib json file. Where can I get/generate the dataset you were using?

	▲	fpoling a day ago \| parent [-]
		The dataset is internal, but if you get a bunch of web pages from wikipedia and wrap them into HTML then it give a rough idea. With 4K LUKS sectors the write speed is too low for a modern SSD. Check that LUKS use a fast implementation. I have: `$ /usr/sbin/cryptsetup benchmark ... # Algorithm \| Key \| Encryption \| Decryption aes-cbc 128b 664.1 MiB/s 2615.9 MiB/s` ... aes-xts 512b 2708.8 MiB/s 2986.0 MiB/s and my LUKS setup uses aes-xts 512b.