Re: BHYVE on NFSv4.2 filesystem?

Rick Macklem <[email protected]> Mon, 18 May 2026 15:28:52 -0700
Newsgroups gmane.os.freebsd.devel.hackers
Message-ID <CAM5tNy4wPkOJPhRRvVHBuW48mSa25zSMEVo=OumPChO3H1xUpg@mail.gmail.com>
On Mon, May 18, 2026 at 3:18 PM Rick Macklem <[email protected]> wrote:
>
> On Mon, May 18, 2026 at 3:01 PM Dan Shelton <[email protected]> wrote:
> >
> > On Mon, 18 May 2026 at 23:49, Rick Macklem <[email protected]> wrote:
> > >
> > > On Mon, May 18, 2026 at 2:27 PM Dan Shelton <[email protected]> wrote:
> > > >
> > > > On Fri, 20 Feb 2026 at 01:21, Bakul Shah <[email protected]> wrote:
> > > > >
> > > > > On Feb 19, 2026, at 11:45 AM, Dan Shelton <[email protected]> wrote:
> > > > > >
> > > > > > On Wed, 18 Feb 2026 at 22:45, Dan Shelton <[email protected]> wrote:
> > > > > >>
> > > > > >> Hello,
> > > > > >>
> > > > > >> Has anyone tried a BHYVE with a disk as file on a NFSv4.2 mount?
> > > > >
> > > > > Yes. [I tried this on a 15.0-RELEASE-p3 host, nfsv4.2 mounting
> > > > > a filesystem from a 15.0-STABLE machine]
> > > >
> > > > How about the performance? Is it better than iSCSI?
> > > >
> > > > >
> > > > > >
> > > > > > And does BHYVE disk emulation send a NFSv4.2 DEALLOCATE if the disk
> > > > > > gets a TRIM cmd?
> > > > >
> > > > > No idea.
> > > >
> > > > Which tool can be used to figure that out? dtrace on the FreeBSD
> > > > NFSv4.2 client? Rick?
> > > Ask google's ai.
> > >
> > > I just typed "does zfs use trim" and it gave me an answer
> > > that looks legit. Is it correct? I don't know, but if you don't
> > > think so, find a ZFS wizzard.
> > >
> > > ZFS is the only local fs that supports DEALLOCATE at this
> > > time, so it is up to ZFS.
> >
> > No, the question is whether the BHYVE disk emulation uses deallocate()
> > to free blocks, and the FreeBSD NFSv4.2 client translates deallocate()
> > to NFSv4.2 DEALLOCATE
> Look for fspacectl() in the bhyve sources with find/grep.
> (fspacectl() is the FreeBSD syscall that does VOP_DEALLOCATE()/
> DEALLOCATE.
Or ask the google ai "does bhyve on freebsd use fspacectl"?

rick

>
> rick
>
> >
> > Dan
> > --
> > Dan Shelton - Cluster Specialist Win/Lin/Bsd
> >