Frankly speaking, I am against saving log in volatile memory or tmpfs.
Most people do it for increasing the life of a $8 microSD card, but forget by doing this they are shortening the life of RAM of of a $35 Pi.
I dont want to save $8 and waste $35 in doing so.
Note: Since for ADSB, an 8Gb microSD card is sufficient, all my microSD cards are only 8Gb Class 10 ($6~$8)
Two of these are 24/7 use in two RPi since begining of 2015.
Other 3 are for experimenting/testing, and have faced innumerable numbers of formatting & reimaging, and all have servived this torture.
And no tmpfs or volatile memory ever used on any of the 5 cards.