Based on what I’ve seen with my use of ZRam I don’t think it reserves the total space, but instead consumes whatever is shown in the output of zramctl --output-all. If you’re swapping then yes it would take memory from the system (up to the 8G disk size), based on how compressible the swapped content is (like if you’re getting a 3x ratio it’s 8GB/3=2.6GB). That said - it will take memory from the disk cache if you’re swapping.
Realistically I think your issue is IO and there’s not much you can do with if your disk cache is being flushed. Switching to zswap might help as it should spill more into disk if you’re under memory pressure.
Based on what I’ve seen with my use of ZRam I don’t think it reserves the total space, but instead consumes whatever is shown in the output of
zramctl --output-all. If you’re swapping then yes it would take memory from the system (up to the 8G disk size), based on how compressible the swapped content is (like if you’re getting a 3x ratio it’s 8GB/3=2.6GB). That said - it will take memory from the disk cache if you’re swapping.Realistically I think your issue is IO and there’s not much you can do with if your disk cache is being flushed. Switching to zswap might help as it should spill more into disk if you’re under memory pressure.