Powerfail problem

[steve]

Hi all,

It was the metadata not being updated.

When I set my caching to "reads only", all of a sudden code running in my VM can restart properly after a hard power-off.

I don't know why I didn't think of this before, because I knew that metadata wasn't updated in a timely manner with DAX files.

Better late than never!
------------
Steve Heller

[Jeff Moyer]

steve <st...@steveheller.org> writes:

> Hi all,
>
> It was the metadata not being updated.
>
> When I set my caching to "reads only", all of a sudden code running in
> my VM can restart properly after a hard power-off.
>
> I don't know why I didn't think of this before, because I knew that
> metadata wasn't updated in a timely manner with DAX files.

Are you referring to file system metadata? On Linux, you should be
using the MAP_SYNC flag during mmap in order to ensure crash
consistency. If you are using that flag and you still see a problem,
that is a bug.

-Jeff

[steve]

I'm not calling mmap myself; I'm using the llfio library to abstract out the differences between Windows and Linux (among other reasons). I wasn't
setting the caching flag for that library properly when opening the file.
------------
Steve Heller