Hello, Gentoo. I've just bought myself a Samsung NVMe 960 EVO M.2 SSD. (Do I get a prize for the number of inscruitable abbreviations in a row? ;-) The idea is, this will form a core part of my new machine, just as soon as AMD Ryzen motherboards start being reasonably available.
I put it into my current (7½ YO) box to test it out. Physically installing it was no problem at all - I also bought a PCIe carrier card with an M.2 slot. Making Linux see it was also no sweat - I just added the appropriate settings to the device driver bit of the kernel's menuconfig (as detailed in the Gentoo NVMe wiki page), rebuilt and re-installed it and it worked. I'd had some slight worry about how to actually drive this thing. The night before, I'd emerged sys-apps/nvme-cli, and became bewildered by all the things it appears you need to understands for NVMe drives. But my new SSD, /dev/nvme0, already carried a "namespace", /dev/nvme0n1. Before long, the "namespace" had an MS-DOS partition table and two 20GB ext-3 partitions, just to try it out. I copied /usr/portage onto one of these partitions and mounted it at /usr/portage. I mounted the other one at /var/tmp. Some timings: An emerge -puND @world (when there's nothing to merge) took 38.5s. With my mirrored HDDs, this took 45.6s. (Though usually it takes nearer a minute.) An emerge of Firefox took 34m23s, compared with 37m34s with the HDDs. The lack of the sound of the HDD heads moving was either disconcerting or a bit of a relief, I'm not sure which. Copying my email spool file (~110,000 entries, ~1.4 GB) from SSD -> SSD took 6.1s. From HDD RAID -> HDD RAID it took 30.0s. ######################################################################### I must confess to feeling somewhat underwhelmed by this new SSD. I'm quite some way off of the advertised ~3 GB/s read speed and ~1.5 GB/s write speed (which admittedly needs PCIe version 3). Quite likely, I've not got the drive set up optimally, but I think it's connected to the rest of the PC via four PCIe version 2 lanes. (I'll need to work out how to check this.) But in a pure file copy, I'm only getting a factor 5 speed increase over my 7½ year old HDD pair. Doing portage things, it's shaving only modest factors off of the timings. My intention was to have a RAID pair of these NVMe drives in my new box. Now I'm thinking more along the lines of using this NVMe drive for the OS, and a RAID pair of (cheaper) SATA SDDs for precious data - the extra performance that NVMe gives over SATA, although more significant with a modern speed machine than my 7½ year old one, seems unlikely to justify the extra cost. -- Alan Mackenzie (Nuremberg, Germany).
