Re: WRITE_SAME support in FreeBSD nfsd NFSv4.1 mode?

On Sun, Jan 12, 2025 at 12:23 AM Cedric Blancher
<cedric.blancher@gmail.com> wrote:
>
> On Fri, 10 Jan 2025 at 16:02, Alan Somers <asomers@freebsd.org> wrote:
> >
> > On Thu, Jan 9, 2025 at 5:31 PM Dan Shelton <dan.f.shelton@gmail.com> wrote:
> > >
> > > Hello!
> > >
> > > Does FreeBSD nfsd support the WRITE_SAME request in NFSv4.1 mode?
> > >
> > > Dan
> > > --
> > > Dan Shelton - Cluster Specialist Win/Lin/Bsd
> >
> > Out of curiosity, what is your use case?
>
> As discussed in the linux-nfs@ list, is a typical "big data" and
> database accelerator, for example fast pattern fill (1 WRITE_SAME
> command over the write, compared to <n> commands with data block,
> where <n> is typically > 200 average), or just zero fill for blocks.
> It's basically reducing network traffic dramatically.
>
> Windows SMB 3.0 already supports that, and is a main selling point for
> M$ to keep database people on the W$ platform. They even added several
> Windows syscalls like
> https://learn.microsoft.com/en-us/windows/win32/api/winioctl/ni-winioctl-fsctl_set_zero_data
>
> Ced

I understand why WRITE SAME would greatly reduce network traffic
compared to writing the same data n times.  But my question is, what
real application requires that, where the data isn't simply all-zeros?
 Are there database operations that require writing the same non-zero
pattern to multiple blocks?