Re: [PATCH 0/6] power_of_2 emulation support for NVMe ZNS devices

Javier González
2022-03-10T13:15:04Z

> On 10 Mar 2022, at 14.07, Matias Bjørling <matias.bjorling@wdc.com> wrote:
>
> ﻿
>>
>> Yes, these drives are intended for Linux users that would use the zoned
>> block device. Append is supported but holes in the LBA space (due to diff in
>> zone cap and zone size) is still a problem for these users.
>
> With respect to the specific users, what does it break specifically? What are key features are they missing when there's holes?

What we hear is that it breaks existing mapping in applications, where the address space is seen as contiguous; with holes it needs to account for the unmapped space. This affects performance and and CPU due to unnecessary splits. This is for both reads and writes.

For more details, I guess they will have to jump in and share the parts that they consider is proper to share in the mailing list.

I guess we will have more conversations around this as we push the block layer changes after this series.