Re: misleading ZFS warning
Eric Borisch <[email protected]> Thu, 23 Jul 2026 19:17:18 -0500
| Newsgroups | gmane.os.freebsd.devel.file-systems |
|---|---|
| Message-ID | <CAMsT2=kVrZv2YgUwYcZ5TaLAeiJoZhcb7JuYFvacctUj9ghGSQ@mail.gmail.com> |
--0000000000004b612d0657504c4f Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I think it largely is for RAIDZn set ups, which will be severely impacted in turns of utilization for small volblocksizes. It will still impact compression performance: with 4K volblocks and ashift=3D12, you=E2=80=99ll have no ability to leverage compression. - Eric On Thu, Jul 23, 2026 at 1:43=E2=80=AFAM Ronald Klop <[email protected]> = wrote: > For a single disk pool I think you can ignore the warning. I can only > imagine the situation of the warning for a raidz setup. > > Maybe others have more insights. > > > Regards, > Ronald > > *Van:* Anthony Pankov <[email protected]> > *Datum:* 22 juli 2026 17:26 > *Aan:* Ronald Klop <[email protected]> > *CC:* [email protected] > *Onderwerp:* Re: misleading ZFS warning > > > > What is underlying pool structure? > > pool: as1 > state: ONLINE > config: > > NAME STATE READ WRITE CKSUM > as1 ONLINE 0 0 0 > diskid/DISK-WD-C82MNNSK.eli ONLINE 0 0 0 > > one dedicated GELI-encrtypted HDD. > > GELI info: > > Geom name: diskid/DISK-WD-C82MNNSK.eli > State: ACTIVE > EncryptionAlgorithm: AES-XTS > KeyLength: 128 > Crypto: accelerated software > Version: 7 > UsedKey: 0 > Flags: NONE > KeysAllocated: 1398 > KeysTotal: 1398 > Providers: > 1. Name: diskid/DISK-WD-C82MNNSK.eli > Mediasize: 6001175121920 (5.5T) > Sectorsize: 4096 > Mode: r1w1e1 > > > > Wednesday, July 22, 2026, 6:12:00 PM, you wrote: > > > What is underlying pool structure? > > Zraid/mirror/single disk? > > > If zraid, what is the stripesize? > > > Regards, > > Ronald > > > Van: Anthony Pankov > > Datum: 22 juli 2026 11:51 > > Aan: [email protected] > > Onderwerp: misleading ZFS warning > > >> > > Hello, > >> > Doing this: > >> > zfs create -b 4096 -o volmode=3Ddev -V 32G as1/dockerim/dsk.adock= er > >> > I've got > >> > Warning: volblocksize (4096) is less than the default minimum block > size (16384). > >> To reduce wasted space a volblocksize of 16384 is recommended. > >> > While ashift=3D12 for this pool I can't understand am I really do > something wrong and there will be "wasted space" or this is a misleading > warning. > >> > Can somebody enlight this? > >> > -- > Best regards, > >> Anthony Pankov mailto:[email protected]= m > > > > -- > Best regards, > Anthony > > ------------------------------ > > > > > --0000000000004b612d0657504c4f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"auto">I think it largely is for RAIDZn set ups, which will be s= everely impacted in turns of utilization for small volblocksizes. It will s= till impact compression performance: with 4K volblocks and ashift=3D12,</di= v><div dir=3D"auto">=C2=A0you=E2=80=99ll have no ability to leverage compre= ssion.</div><div dir=3D"auto"><br></div><div dir=3D"auto">- Eric</div><div>= <br><div class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" class= =3D"gmail_attr">On Thu, Jul 23, 2026 at 1:43=E2=80=AFAM Ronald Klop <<a = href=3D"mailto:[email protected]">[email protected]</a>> wrote:<br= ></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-= left:1px #ccc solid;padding-left:1ex"><div>For a single disk pool I think y= ou can ignore the warning. I can only imagine the situation of the warning = for a raidz setup.=C2=A0<br><br>Maybe others have more insights.</div><div>= <br><br>Regards,<br>Ronald<br><br><p><small><strong>Van:</strong> Anthony P= ankov <<a href=3D"mailto:[email protected]" target=3D"_blank">ant= [email protected]</a>><br><strong>Datum:</strong> 22 juli 2026 17:26= <br><strong>Aan:</strong> Ronald Klop <<a href=3D"mailto:ronald-lists@kl= op.ws" target=3D"_blank">[email protected]</a>><br><strong>CC:</stron= g> [email protected]<br><strong>Onderwerp:</strong> Re: misleading ZFS warning= <br></small></p><blockquote style=3D"margin-left:5px;border-left:3px solid = #ccc;margin-right:0px;padding-left:5px"><div id=3D"m_-6946508591058687342P"= > <div id=3D"m_-6946508591058687342P.P"><br> > =C2=A0What is underlying pool structure?<br> <br> =C2=A0pool: as1<br> =C2=A0state: ONLINE<br> config:<br> <br> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0NAME =C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0STATE =C2=A0=C2= =A0=C2=A0=C2=A0READ WRITE CKSUM<br> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0as1 =C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0ONLINE = =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00 =C2=A0=C2=A0=C2=A0=C2=A00 =C2=A0=C2= =A0=C2=A0=C2=A00<br> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0diskid/DISK-WD-= C82MNNSK.eli =C2=A0ONLINE =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00 =C2=A0=C2= =A0=C2=A0=C2=A00 =C2=A0=C2=A0=C2=A0=C2=A00<br> <br> one dedicated GELI-encrtypted HDD.<br> <br> GELI info:<br> <br> Geom name: diskid/DISK-WD-C82MNNSK.eli<br> State: ACTIVE<br> EncryptionAlgorithm: AES-XTS<br> KeyLength: 128<br> Crypto: accelerated software<br> Version: 7<br> UsedKey: 0<br> Flags: NONE<br> KeysAllocated: 1398<br> KeysTotal: 1398<br> Providers:<br> 1. Name: diskid/DISK-WD-C82MNNSK.eli<br> =C2=A0=C2=A0=C2=A0Mediasize: 6001175121920 (5.5T)<br> =C2=A0=C2=A0=C2=A0Sectorsize: 4096<br> =C2=A0=C2=A0=C2=A0Mode: r1w1e1<br> <br> <br> <br> Wednesday, July 22, 2026, 6:12:00 PM, you wrote:<br> <br> > What is underlying pool structure?<br> > Zraid/mirror/single disk?<br> <br> > If zraid, what is the stripesize?<br> <br> > Regards,<br> > Ronald<br> <br> > Van: Anthony Pankov <u></u><br> > Datum: 22 juli 2026 11:51<br> > Aan: [email protected]<br> > Onderwerp: misleading ZFS warning<br> <br> >> > > Hello,<br> >> > Doing this:<br> >> > =C2=A0zfs create =C2=A0-b 4096 -o volmode=3Ddev =C2=A0-V 32G = as1/dockerim/dsk.adocker<br> >> > I've got<br> >> > Warning: volblocksize (4096) is less than the default minimum= block size (16384).<br> >> To reduce wasted space a volblocksize of 16384 is recommended.<br> >> > While ashift=3D12 for this pool I can't understand am I r= eally do something wrong and there will be "wasted space" or this= is a misleading warning.<br> >> > Can somebody enlight this?<br> >> > -- > Best regards,<br> >> =C2=A0Anthony Pankov =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0mailto:<a href=3D"mailto:[email protected]" = target=3D"_blank">[email protected]</a><br> <br> <br> <br> --=C2=A0<br> Best regards,<br> Anthony<br> <br> <u></u></div> <hr> </div> </blockquote><br><br><br></div></blockquote></div></div> --0000000000004b612d0657504c4f--