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 -sFilename                                Type            Size    Used    Priority/dev/mapper/debian_crypt-swap           partition       2097148 0       10/dev/zram0                              partition       255996  203404  70/dev/zram1                              partition       255996  203284  70I found a script zraminfo which can calculate the compression ratio: # ./zraminfo.shPhysical memory:      1,049,821,184 bytesBuffers and cache:      116,097,024 bytes / 11.1% of total memoryUnallocated:             81,043,456 bytes /  7.7% of total memoryCompressed:             121,118,720 bytes / 11.5% of total memoryUncompressed size:      346,472,448 bytes / 2.861 compression ratioSo, 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?
How much RAM is there?
zram