FreeBSD and Linux SSD Write Speeds

[Tim Daneliuk]

Disclaimer: Tests below run on lightly loaded systems, but results are ... surprising:

Test Case: dd if=/dev/zero of=foo bs=8M count=512

Linux 4.4.0-21-generic on a 2.66GHz Core2 Duo w/8GB memory, older OCZ SSD/ext4:  310MB/sec writes

FreeBSD 10-STABLE on an 3.2 GHz Quad Core i5 w/8GB memory, newer Kingston SSD/ufs:  210MB/sec writes

Results are repeatable.

So, what is the likely culprit making FreeBSD 1/3 slower?  The FreeBSD system does does / nfs exported (which I don't quite yet understand since all the nfs mount points are below it) at the moment, but there is little or no nfs traffic.