I installed Kubuntu 15.04 with BTRFS file system and 4GB of ram. After a while memory becomes full and browser crashes. I was going to see if SWAP is doing its work just to find out that BTRFS does not support SWAP So if you are going to use BTRFS make sure you have at least 8GB of RAM, other than that it works nice. I reinstalled it and used "ext4, swap and boot" partition model since system is to old for upgrades...
