[dm-devel] Question about which types of dm need to support DAX

[y-goto at fujitsu.com]

Hello Jeff-san,

> "Yang, Xiao/杨 晓" <yangx.jy at fujitsu.com> writes:
> 
> > Hi Jeff,
> >
> > Thanks a lot for your reply.
> >
> > On 2022/9/27 3:52, Jeff Moyer wrote:
> >> "Yang, Xiao/杨 晓" <yangx.jy at fujitsu.com> writes:
> >>
> >>> Hi Ross, Toshi, Jeff and others
> >>>
> >>> After reading the kernel patches[1][2][3] about dm, I think only
> >>> three types(linear, stripe and log-writes) of dm can support DAX now,
> right?
> >>
> >> Right.
> >>
> >>> I wonder why only three types of dm need to support DAX? Is there
> >>> any reason/history and use case?
> >>
> >> It was easy to add DAX support to those targets.  Note that if a
> >> target needs to intercept I/O, then it is fundamentally incompatible with
> DAX.

I would like to know its use case.
Though my team has been made effort for a long time to remove experimental of FS-DAX,
we still need one more time to solve thin-pool (or other DM feature) v.s. DAX problem even if it is easy.

To be honest, I'm under criticism for taking such a long time and still not be able to remove experimental.
In addition, there are a few persons who insist Fujitsu should stop development of FS-DAX due to
too much time for development

I hope that my team can continue to make effort for FS-DAX.
If there is a use-case of thin-pool, then I'll be able to persuade such persons by it. 
So I would appreciate it if you could tell me about the use case.

Thanks,
---
Yasunori Goto