Date: Mon, 7 Dec 2020 09:14:47 +0530 From: Krishnamraju Eraparaju <ekraju@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Yuri Pankov <yuripv@yuripv.dev>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: when to use "/dev/nvme0ns1" Message-ID: <CAC-Y4SQe8a80kUxFb3W_R=%2Bc3WM005_v%2Bzss_aHGM8q5=GGJCA@mail.gmail.com> In-Reply-To: <CANCZdfrHG=S75bFfuu5F4ezs1OJ-mS%2BDXjMGOZL5WbX4r6q9ZQ@mail.gmail.com> References: <CAC-Y4SRKsYspBBHHUs4dVJxAiO03FK6jfLJ23bY=vNQfUnA_qQ@mail.gmail.com> <10a5e607-a852-716a-9872-984e7247996e@yuripv.dev> <CANCZdfrHG=S75bFfuu5F4ezs1OJ-mS%2BDXjMGOZL5WbX4r6q9ZQ@mail.gmail.com>
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Thank you Warner Losh & Yuri Pankov. Can I use nvmeXnsY for IO? Looks like fio shows better performance with nvmeXnsY, then nvd/nda devices= . Thanks, ekraju. On Sun, Dec 6, 2020 at 11:13 AM Warner Losh <imp@bsdimp.com> wrote: > > > On Sat, Dec 5, 2020 at 10:36 PM Yuri Pankov <yuripv@yuripv.dev> wrote: > >> Krishnamraju Eraparaju wrote: >> > Hi All, >> > >> > >> > I see there are two ways of accessing NVMe disk: >> > 1)GEOM based: /dev/nvd0 or /dev/nda0 >> > 2)/dev/nvme0ns1 >> > >> > When should one use " /dev/nvme0ns1"? >> >> See nvmecontrol(8) for the commands that operate on namespace ids. And >> while you could still use nvd/nda devices for those, specifying the >> namespace explicitly could be helpful. >> >> An excerpt from man page: >> >> DEVICE NAMES >> Where =E2=9F=A8namespace-id=E2=9F=A9 is required, you can use eith= er the nvmeXnsY >> device, or the disk device such as ndaZ or nvdZ. The leading /dev= / >> is omitted. >> > > Yes. nvd* and nda* are block devices. nvme0ns1 is for administrative > things when you may or may not have an nda/nvd device hanging around, or > you want to deal with a specific thing and don't know the mapping to the > nda/nvd device. > > Warner >
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