Jeremy Nicoll <jn.ml.dbn.25@letterboxes.org> wrote:
On Wed, 7 Oct 2020, at 09:39, Hans wrote:
I have a little question. Smartctl is telling me, that my ssd drive
is 6Gb/sec capable, but the actual speed is only 1,5GB/sec.
If your SATA (presumably) connection from the machine to the SSD is a
6 Gbps one, the maximum data transfer speed in bytes across that
connection would be one eighth of that (as there's 8 bits per byte),
so about 760 MBps.
That's about half of your "1,5GBps". That makes me wonder if your SSD
uses two SATA channels at once - is that even possible?
Only with SAS drives. And usually only for redudancy and not for
concurrency.
I question the benchmark Hans did.
Something tells me he either used "hdparm -tT", which is known to
misrepresent the speeds on modern drives, or wrote too little data so he
was benchmarking the Kernel cache and not the drive.