I'm trying to estimate how effective the zram kernel module is in case of my PC. I have a pretty old machine (7y) with the only 1 GiB of RAM.
I created two zram swaps (two core processor), 250MiB each, and everything seems to be working:
# swapon -s
Filename Type Size Used Priority
/dev/mapper/debian_crypt-swap partition 2097148 0 10
/dev/zram0 partition 255996 203404 70
/dev/zram1 partition 255996 203284 70
I found a script zraminfo which can calculate the compression ratio:
# ./zraminfo.sh
Physical memory: 1,049,821,184 bytes
Buffers and cache: 116,097,024 bytes / 11.1% of total memory
Unallocated: 81,043,456 bytes / 7.7% of total memory
Compressed: 121,118,720 bytes / 11.5% of total memory
Uncompressed size: 346,472,448 bytes / 2.861 compression ratio
So, after decompressing 121M, I will get +200M extra. But one thing, why is there 200M in each zram device? Shouldn't be there 2*200M compressed data, and 1,2G uncompressed?
