Re: NFSv4.2 DEALLOCATE working in FreeBSD 15.0?

In reply to: Aurélien_Couderc : "NFSv4.2 DEALLOCATE working in FreeBSD 15.0?"
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From: Rick Macklem <rick.macklem_at_gmail.com>
Date: Tue, 06 Jan 2026 21:56:10 UTC

On Tue, Jan 6, 2026 at 1:17 PM Aurélien Couderc
<aurelien.couderc2002@gmail.com> wrote:
>
> Can NFSv4.2 DEALLOCATE be used with FreeBSD nfsd to create sparse files?
If you are exporting ZFS file systems then, yes, within the ZFS recordsize
limitations, afaik. (I'm not a ZFS guy, but I can see that
zfs_deallocate() calls
zfs_freesp(), which I think does result is space deallocation?)

Other file systems, such as UFS, no. (For the non-ZFS ones, DEALLOCATE just
writes blocks of zeros, it does not release the storage.)

At least that is my understanding, not being a ZFS guy, rick


>
> Aurélien
> --
> Aurélien Couderc <aurelien.couderc2002@gmail.com>
> Big Data/Data mining expert, chess enthusiast
>