The script [log2ram](https://github.com/azlux/log2ram) can work on every linux system. So you can use it with your own daemon manager if you don't have systemd.
Into the file `log2ram` (or `/usr/local/bin/log2ram` if you have already installed it), there are two variables into the script : `SIZE=40M` and `USE_RSYNC=false`
The first variable define the size the log folder will reserve into the RAM.
The second variable can be set to `true` if you prefer "rsync" than "cp". I use the command `cp -u` and `rsync -X`, I don't copy the all folder every time for optimization.
#### refresh time:
The default is to write log into the HardDisk every hour. If you think this is too much, you can make the write every day by moving the cron file : `sudo mv /etc/cron.hourly/log2ram /etc/cron.daily/log2ram`.