On 04/08/19 19:29, Chris Cappuccio wrote:
gwes [g...@oat.com] wrote:
What is the rated transfer rate of the SSD you're using to test?
SATA 3 wire speed is 6G/sec and realistically 500MB/sec raw rate
is near the top.
Anything over that is an artefact probably from a cache somewhere.
He's using NVMe with its own DRAM cache, which should perform higly. There
is a limiter somewhere, it seems.
That doesn't answer the question: if you say
dd if=/dev/zero of=/dev/sda (linux) /dev/rsd0c (bsd) bs=64k count=1000000
what transfer rate is reported
That number represents the maximum possible long-term filesystem
performance on that drive.
There are other non-filesystem overheads which have to be excluded
before you can be sure that the differences are truly the filesystem
code and algorithms without cache differences.