On Fri, Jun 3, 2016 at 10:31 AM, Johannes Thumshirn jthumshirn@suse.de wrote:
On Thu, Jun 02, 2016 at 04:21:22PM -0400, Greg Freemyer wrote:
On Thu, Jun 2, 2016 at 3:56 PM, Andrei Borzenkov arvidjaar@gmail.com wrote:
02.06.2016 16:27, Greg Freemyer пишет:
=== M.2 M Key device using AHCI protocol ===
Samsung XP941 SSD PCIe M Key 2280 MZHPU128HCGM-00000
AHCI is _not_ NVMe!!!
While that is true ...
AHCI is SATA.
... this is not always. M.2 storage can be connected either using SATA to HBA on motherboard or it can be connected using PCIe to PCIe switch on motherboard. In the latter case it can either contain AHCI compatible controller *on M.2 card itself* or it can contain NVMe compatibel controller. In both cases host interface is still PCIe which provides advantage over plain SATA.
The above card seems to be AHCI over PCIe, so no SATA :)
That's the trickery with the M.2 Slot. It can be SATA, USB or PCIe.
$120 from Amazon
JFTR I've made good experiences with the following Samsung M.2 NVMe: # nvme list Node Model Version Namepace Usage Format FW Rev
/dev/nvme0n1 SAMSUNG MZVPV256HDGL 1.1 1 26,26 GB / 256,06 GB 512 B + 0 B BXW72H0Q
Yes, and this one is NVMe (NVM over PCIe).
...
Do you know if a PCIe adapter card has to support AHCI vs NVMe, or does the PCIe card just connect the PCIe bus pins to the M.2 connector pins and could careless what protocol is in use?
As far as I know in case M.2 AHCI over PCIe everything is implemented on M.2 card itself, and it just needs pure PCIe interface.