On 17.06.2020 08:01, Martin K. Petersen wrote:
Because Append is the way to go and we've moved the Linux zoned block
I/O stack to required it,
Just to add some historical context: The first discussions about how to
support block devices with a non-random write model in Linux happened
maybe a decade ago.
Drive vendors came to LSF/MM to solicit feedback on how Linux could
support impending SMR devices. We spent a long time going over various
approaches, including some that are similar to what is now being
entertained as alternative to Append. The conclusion back then was that
an Append-like model (tell-us-where-you-put-it) was the only reasonable
way to accommodate these devices in Linux given how our filesystems and
I/O stack worked.
Consequently, I don't think it is at all unreasonable for us to focus on
devices that implement that mode of operation in the kernel. This is
exactly the that we as a community asked the storage industry to
provide!
Martin,
Thanks for sharing the historical context. I agree that append solves a
number of problems in Linux - we have had internal implementations of
append for a long time (and are sending patches extending support for it
later today).
This said, there are users that do not see append as a good fit for
their needs and we would like to support them too.
We will go back to our code and re-iterate based on the feedback we have
gotten out of this thread.
Thanks,
Javier
