Date: Mon, 6 Nov 2023 01:34:32 +0100 From: Martin Matuska <mm@FreeBSD.org> To: FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: Is 14.0 to released based on 0 for sysctl vfs.zfs.bclone_enabled ? Message-ID: <05b493bc-94a5-4c78-bebf-5581addc5b7b@FreeBSD.org> In-Reply-To: <830CD3A8-DB62-418D-A7F7-8DA6CB46B1F5@yahoo.com> References: <2F81D978-7DBD-42CE-8ECF-C020B0CB5C29.ref@yahoo.com> <2F81D978-7DBD-42CE-8ECF-C020B0CB5C29@yahoo.com> <7a906956-6836-421e-b25e-ff701369e3ed@FreeBSD.org> <BBFDD30F-FB5D-44C8-ADA7-5B5AF859D86A@karels.net> <830CD3A8-DB62-418D-A7F7-8DA6CB46B1F5@yahoo.com>
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OpenZFS 2.2.0 in FreeBSD 14 fully supports block cloning. You can work with pools that have feature@block_cloning enabled. The sysctl variable vfs.zfs.bclone_enabled affects the behavior of zfs_clone_range() which is called by copy_file_range(). When it is set to 0, zfs_clone_range() does not do block cloning. If it is set to anything else than 0, zfs_clone_range() does block cloning (if all conditions are met - same ZFS pool, correct data alignment, etc.). In FreeBSD-main, this tunable is enabled and I plan to enable it in stable/14 somewhere around December 11, 2023. As of today I personally use block cloning on all my systems. mm On 04/11/2023 13:35, Mark Millard wrote: > On Nov 4, 2023, at 04:38, Mike Karels <mike@karels.net> wrote: > >> On 4 Nov 2023, at 4:01, Ronald Klop wrote: >> >>> On 11/4/23 02:39, Mark Millard wrote: >>>> It looks to me like releng/14.0 (as of 14.0-RC4) still has: >>>> >>>> int zfs_bclone_enabled; >>>> SYSCTL_INT(_vfs_zfs, OID_AUTO, bclone_enabled, CTLFLAG_RWTUN, >>>> &zfs_bclone_enabled, 0, "Enable block cloning"); >>>> >>>> leaving block cloning effectively disabled by default, no >>>> matter what the pool has enabled. >>>> >>>> https://www.freebsd.org/releases/14.0R/relnotes/ also reports: >>>> >>>> QUOTE >>>> OpenZFS has been upgraded to version 2.2. New features include: >>>> • >>>> block cloning, which allows shallow copies of blocks in file >>>> copies. This is optional, and disabled by default; it can be >>>> enabled with sysctl vfs.zfs.bclone_enabled=1. >>>> END QUOTE >>>> >>> >>> I think this answers your question in the subject. >> I think so too (and I wrote that text). > Thanks for the confirmation of the final intent. > > I believe this makes: > > QUOTE > author Brian Behlendorf <behlendorf1@llnl.gov> 2023-05-25 20:53:08 +0000 > committer GitHub <noreply@github.com> 2023-05-25 20:53:08 +0000 > commit 91a2325c4a0fbe01d0bf212e44fa9d85017837ce (patch) > tree dd01dfce6aeef357ade1775acf18aade535c6271 > . . . > Update compatibility.d files > > Add an openzfs-2.2 compatibility file for the next release. Edon-R > support has been enabled for FreeBSD removing the need for different > FreeBSD and Linux files. Symlinks for the -linux and -freebsd names > are created for any scripts expecting that convention. Additionally, a > symlink for ubunutu-22.04 was added. Signed-off-by: Brian Behlendorf > <behlendorf1@llnl.gov> Closes #14833 > END QUOTE > > technically incorrect in that compatibility.d/openzfs-2.2-freebsd > should be distinct in content from compatibility.d/openzfs-2.2 so > that block cloning would not be enabled. > > >>>> Just curiousity on my part about the default completeness of >>>> openzfs-2.2 support, not an objection either way. >>>> >>> >>> I haven't seen new issues with block cloning in the last few weeks >>> mentioned on the mailing lists. All known issues are fixed AFAIK. >>> But I can imagine that the risk+effect ratio of data corruption is >>> seen as a bit too high for a 14.0 release for this particular >>> feature. That does not diminish the rest of the completeness of >>> openzfs-2.2. >>> >>> NB: I'm not involved in developing openzfs or the decision making in >>> the release. Just repeating what I read on the lists. >> There was another block cloning fix in 14.0-RC4; see the commit log. >> Maybe there will be no more issues, but it seems that corner cases were >> still being found recently. > Looks like I'll stay at openzfs-2.1 pool features until there is > a release that no longer has the default status: > > 0 for sysctl vfs.zfs.bclone_enabled > > I use main [so: 15 now] but only enable openzfs-2.* pool features > supported by default on some FreeBSD release, that has an accurate > compatibility.d/openzfs-2.*-freebsd file. > > === > Mark Millard > marklmi at yahoo.com > >
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