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From: hch@infradead.org (Christoph Hellwig)
Subject: How /dev/nvme numbers are allocated/mapped to BDF
Date: Fri, 3 Aug 2018 00:18:20 -0700	[thread overview]
Message-ID: <20180803071820.GA22003@infradead.org> (raw)
In-Reply-To: <073447516980487e950bbc428225ae02@ausx13mps321.AMER.DELL.COM>

On Thu, Aug 02, 2018@10:09:50PM +0000, Alex_Gagniuc@Dellteam.com wrote:
> Hi,
> 
> Recently some confusion came up about how the /dev/nvme numbers are 
> allocated, and how much one can expect the to be consistent across 
> reboots. I was fairly convinced that it was about as random as a coin 
> flip, but some people have pointed out that these numbers were very 
> deterministic in older kernels, dating back to the 3.10 era.

They are allocated using an ida allocator and are not stable at all.
For any stable enumeration you have to rely on the EUI64/NGUID/UUID.

> Also, separate but related question. Samsung M1725a drives don't 
> generate entries under /dev/disk/by-path. Any idea why that might be?

Please send a dump of the nvme-cli id-ctrl subcommand.

  reply	other threads:[~2018-08-03  7:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-02 22:09 How /dev/nvme numbers are allocated/mapped to BDF Alex_Gagniuc
2018-08-03  7:18 ` Christoph Hellwig [this message]
2018-08-03 14:40   ` Keith Busch
2018-08-03 16:16     ` Alex_Gagniuc
2018-08-03 16:54       ` Keith Busch
2018-08-03 16:58         ` Johannes Thumshirn
2018-08-03 17:07           ` Keith Busch
2018-08-03 17:20         ` Alex_Gagniuc
2018-08-03 17:40           ` Keith Busch
2018-08-04  8:16         ` Christoph Hellwig
2018-08-05 15:48           ` Alex_Gagniuc

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