Ok, so I have 8GB memory and 30GB msata storage + some external drives...
30GB for ubuntu, no SWAP partition, only main /
Updated fstab to store /tmp and /var/log into RAM and Firefox caching into /tmp
But my RAM is filled very fast. I cannot run computer 24 hours without a problem. After long time I reach storage capacity of msata drive and RAM. 30GB is filled with ~/.cache/upstart (I just delete it :-D ) and RAM is filled.... I do not know reason. Checked /var/log and /tmp but it is not big enough to fill my memory.
fstab:
UUID=d12c3921-b2d3-49d4-a55b-fd22683c4b6d / ext4 noatime,errors=remount-ro 0 1
#
# Modification for SSD
tmpfs /var/log tmpfs defaults,noatime 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0