Should I turn on innodb_strict_mode and add primary key to tables with no primary keys

[vitachaos]

@Not that fast hdd's and 250mbps internet connection - i/o waits

Warning. Do not use O_DSYNC and doublewrite=0 unless you are using a journaling filsystem like btrfs…

so in my case the file system is ext4 ! does ext fall in the same category as btrfs ?