'nvme list' shows 100% usage on empty drives

[Eric Robinson]

Keith,

Yours is the first coherent explanation we've heard. Thank you. The only thing that concerns me is that we had this problem once before, about two years ago, and I cannot find my notes about how I fixed it. I remember that I ran a command (maybe wipefs, fdisk, sedutil, or something similar) and it corrected the problem. After running the command, I ran 'nvme list' multiple times, and each time the "Used" amount kept going down, until it eventually stabilized at 4k. If the issue is with the controller, any idea what would account for that behavior?

-----Original Message-----
From: Keith Busch <kbusch at kernel.org>
Sent: Friday, May 9, 2025 1:27 PM
To: Eric Robinson <eric.robinson at psmnv.com>
Cc: linux-nvme at lists.infradead.org
Subject: Re: 'nvme list' shows 100% usage on empty drives

On Fri, May 09, 2025 at 03:46:03PM +0000, Eric Robinson wrote:
> Why does 'nvme list' show drives as fully used when they are not? Note that 4 of the drives show as fully used. These drives have been secure-erased.

The value here comes from your controller; "nvme list" is just the messenger. The utilization is the Identify Namespace "NUSE" (Namespace
Utilization) field as reported by your controller.

The spec indicates this field is optional, section 2.1.1 of NVM Command Set specification says: "the controller (...) may report a value in the Namespace Utilization field that is always equal to the value in the Namespace Capacity field." Sounds like your controller opted to use that behavior.
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