Re: misleading ZFS warning

Ronald Klop <[email protected]> Thu, 23 Jul 2026 08:42:38 +0200 (CEST)
Newsgroups gmane.os.freebsd.devel.file-systems
Message-ID <1087535779.8809.1784788958495@localhost>
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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=dev  -V 32G as1/dockerim/dsk.adocker
> >> > 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=12 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]
> 
> 
> 
> -- 
> Best regards,
> Anthony
> 
> 
> 
> 
> 
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<html><head></head><body>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.&nbsp;<br class="rw_extra"><br>Maybe others have more insights.<br class="rw_extra"><br>Regards,<br class="rw_extra">Ronald<br class="rw_extra"><br><p><small><strong>Van:</strong> Anthony Pankov &lt;[email protected]&gt;<br><strong>Datum:</strong> 22 juli 2026 17:26<br><strong>Aan:</strong> Ronald Klop &lt;[email protected]&gt;<br><strong>CC:</strong> [email protected]<br><strong>Onderwerp:</strong> Re: misleading ZFS warning<br></small></p><blockquote style="margin-left: 5px; border-left: 3px solid #ccc; margin-right: 0px; padding-left: 5px;"><div class="MessageRFC822Viewer" id="P"><!-- P -->
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&gt; &nbsp;What is underlying pool structure?<br>
<br>
&nbsp;pool: as1<br>
&nbsp;state: ONLINE<br>
config:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NAME &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;STATE &nbsp;&nbsp;&nbsp;&nbsp;READ WRITE CKSUM<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;as1 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ONLINE &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0 &nbsp;&nbsp;&nbsp;&nbsp;0 &nbsp;&nbsp;&nbsp;&nbsp;0<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;diskid/DISK-WD-C82MNNSK.eli &nbsp;ONLINE &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0 &nbsp;&nbsp;&nbsp;&nbsp;0 &nbsp;&nbsp;&nbsp;&nbsp;0<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>
&nbsp;&nbsp;&nbsp;Mediasize: 6001175121920 (5.5T)<br>
&nbsp;&nbsp;&nbsp;Sectorsize: 4096<br>
&nbsp;&nbsp;&nbsp;Mode: r1w1e1<br>
<br>
<br>
<br>
Wednesday, July 22, 2026, 6:12:00 PM, you wrote:<br>
<br>
&gt; What is underlying pool structure?<br>
&gt; Zraid/mirror/single disk?<br>
<br>
&gt; If zraid, what is the stripesize?<br>
<br>
&gt; Regards,<br>
&gt; Ronald<br>
<br>
&gt; Van: Anthony Pankov <[email protected]><br>
&gt; Datum: 22 juli 2026 11:51<br>
&gt; Aan: [email protected]<br>
&gt; Onderwerp: misleading ZFS warning<br>
<br>
&gt;&gt; &gt; &gt; Hello,<br>
&gt;&gt; &gt; Doing this:<br>
&gt;&gt; &gt; &nbsp;zfs create &nbsp;-b 4096 -o volmode=dev &nbsp;-V 32G as1/dockerim/dsk.adocker<br>
&gt;&gt; &gt; I've got<br>
&gt;&gt; &gt; Warning: volblocksize (4096) is less than the default minimum block size (16384).<br>
&gt;&gt; To reduce wasted space a volblocksize of 16384 is recommended.<br>
&gt;&gt; &gt; While ashift=12 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.<br>
&gt;&gt; &gt; Can somebody enlight this?<br>
&gt;&gt; &gt; -- &gt; Best regards,<br>
&gt;&gt; &nbsp;Anthony Pankov &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mailto:[email protected]<br>
<br>
<br>
<br>
--&nbsp;<br>
Best regards,<br>
Anthony<br>
<br>
</[email protected]></div><!-- TextPlainViewer -->
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