Date: Tue, 30 Sep 2025 13:50:04 -0600 From: Warner Losh <imp@bsdimp.com> To: Brandon Allbery <allbery.b@gmail.com> Cc: Rick Macklem <rick.macklem@gmail.com>, Graham Perrin <grahamperrin@gmail.com>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: bsdinstall: system requirements: memory/RAM: ZFS: 2048 MB for an ordinary installation plus a desktop environment Message-ID: <CANCZdfrdKJdJ_vSfErZxXv7H_zeF-GKBagm4fG9rU8JVkbg8Jw@mail.gmail.com> In-Reply-To: <CAKFCL4V9U=CF%2BstGa2j8e%2Bm2LSHsn1UcScwAsK9fbgJ4vGSWJA@mail.gmail.com> References: <20250927203411.E6790B633@freefall.freebsd.org> <zlodcczlzdsmbriedisg@hobq> <714becfe-6772-4761-857e-d32700666e0b@gmail.com> <8c3cb94b-c1b5-45d2-9ac7-1502c4e6409c@gmail.com> <580e3d70-9969-4895-b641-b4343f675084@gmail.com> <CANCZdfpV8mA9YxLqq5SUFmskWupi1Q1=ehC_m5ptDQO7C5iecw@mail.gmail.com> <CAM5tNy5pg=twm7-sM2H7zUbqdVV7zzr7CuWTF4mjFkNMGpmOzg@mail.gmail.com> <CAKFCL4V9U=CF%2BstGa2j8e%2Bm2LSHsn1UcScwAsK9fbgJ4vGSWJA@mail.gmail.com>
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[-- Attachment #1 --] Yea, I've not seen that to be the case. ZFS isn't that big of a memory hog these days... There are times you do need to tune the arc, but they are the exception, not the rule. Warner On Tue, Sep 30, 2025 at 1:41 PM Brandon Allbery <allbery.b@gmail.com> wrote: > FWIW my understanding is that ZFS root is such a memory hog that anything > under 16GB is disrecommended and 32GB preferable. (I have only one > machine that fits that constraint, and FreeBSD doesn't quite work on it > yet.) > > On Tue, Sep 30, 2025 at 3:38 PM Rick Macklem <rick.macklem@gmail.com> > wrote: > >> On Sun, Sep 28, 2025 at 7:59 AM Warner Losh <imp@bsdimp.com> wrote: >> > >> > >> > >> > On Sun, Sep 28, 2025, 4:47 AM Graham Perrin <grahamperrin@gmail.com> >> wrote: >> >> >> >> Follow-up to < >> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287719#c6>; >> >> >> >> Good news. >> >> >> >> 2048 MB is sufficient with root-on-ZFS for an ordinary installation >> >> (more than base, less than all of FreeBSD-base) of 15.0-ALPHA4 >> >> plus these five non-base packages, some of which are meta: >> >> >> >> kde plasma6-sddm-kcm sddm virtualbox-guest-additions xorg >> >> >> >> Beyond initial installations: with 4 G swap enabled, I repeatedly >> >> tested forced reinstallation of all packages, >> >> >> >> pkg upgrade -fUy >> >> >> >> 1077 packages, 1886 steps. Success. >> >> >> >> ---- >> >> >> >> With swap disabled, which I would not recommend: >> >> >> >> - reinstallation failed, switch from ttyv1 to ttyv2 was >> >> impossible, and so on, so I attempted a shut down >> >> <https://i.imgur.com/RftLGMu.png>; >> >> >> >> - shut down failed >> >> >> >> - following a forced stop of the computer, SDDM and the >> >> desktop environment were unsable (pkg issue 2441, >> >> second incident this morning). >> > >> > >> > It's big enough to install.. but i have lxte + terminal + firefox with >> 4 tabs open and I routinely run out of memory and swap heavily. I have a >> 4GB Chromebook. >> Just a wild guess, but I suspect ZFS might be eating your memory. >> You could try something like setting: >> vfs.zfs.arc.max to half of your ram and see what happens? >> >> You probably don't want to do this, but it would be interesting to >> see what happens if you use UFS. >> (Personally, I'd never use ZFS for a root fs, but that's just me.) >> >> rick >> >> > >> > So one can run in 128MB for light tasks and careful kernel tuning, >> 512MB is a more realistic minimum since it lets you install and update. But >> for X it's flipped: you need 2G to install but closer to 4G or 8G to run a >> complete, but on the lean side, X11 system. >> > >> > Warner >> >> >> >> >> >> > > -- > brandon s allbery kf8nh > allbery.b@gmail.com > [-- Attachment #2 --] <div dir="ltr"><div>Yea, I've not seen that to be the case. ZFS isn't that big of a memory hog these days... There are times you do need to tune the arc, but they are the exception, not the rule.</div><div><br></div><div>Warner</div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, Sep 30, 2025 at 1:41 PM Brandon Allbery <<a href="mailto:allbery.b@gmail.com">allbery.b@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">FWIW my understanding is that ZFS root is such a memory hog that anything under 16GB is disrecommended and 32GB preferable. (I have only one machine that fits that constraint, and FreeBSD doesn't quite work on it yet.)</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 30, 2025 at 3:38 PM Rick Macklem <<a href="mailto:rick.macklem@gmail.com" target="_blank">rick.macklem@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Sun, Sep 28, 2025 at 7:59 AM Warner Losh <<a href="mailto:imp@bsdimp.com" target="_blank">imp@bsdimp.com</a>> wrote:<br> ><br> ><br> ><br> > On Sun, Sep 28, 2025, 4:47 AM Graham Perrin <<a href="mailto:grahamperrin@gmail.com" target="_blank">grahamperrin@gmail.com</a>> wrote:<br> >><br> >> Follow-up to <<a href="https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287719#c6" rel="noreferrer" target="_blank">https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287719#c6</a>><br>; >><br> >> Good news.<br> >><br> >> 2048 MB is sufficient with root-on-ZFS for an ordinary installation<br> >> (more than base, less than all of FreeBSD-base) of 15.0-ALPHA4<br> >> plus these five non-base packages, some of which are meta:<br> >><br> >> kde plasma6-sddm-kcm sddm virtualbox-guest-additions xorg<br> >><br> >> Beyond initial installations: with 4 G swap enabled, I repeatedly<br> >> tested forced reinstallation of all packages,<br> >><br> >> pkg upgrade -fUy<br> >><br> >> 1077 packages, 1886 steps. Success.<br> >><br> >> ----<br> >><br> >> With swap disabled, which I would not recommend:<br> >><br> >> - reinstallation failed, switch from ttyv1 to ttyv2 was<br> >> impossible, and so on, so I attempted a shut down<br> >> <<a href="https://i.imgur.com/RftLGMu.png" rel="noreferrer" target="_blank">https://i.imgur.com/RftLGMu.png</a>><br>; >><br> >> - shut down failed<br> >><br> >> - following a forced stop of the computer, SDDM and the<br> >> desktop environment were unsable (pkg issue 2441,<br> >> second incident this morning).<br> ><br> ><br> > It's big enough to install.. but i have lxte + terminal + firefox with 4 tabs open and I routinely run out of memory and swap heavily. I have a 4GB Chromebook.<br> Just a wild guess, but I suspect ZFS might be eating your memory.<br> You could try something like setting:<br> vfs.zfs.arc.max to half of your ram and see what happens?<br> <br> You probably don't want to do this, but it would be interesting to<br> see what happens if you use UFS.<br> (Personally, I'd never use ZFS for a root fs, but that's just me.)<br> <br> rick<br> <br> ><br> > So one can run in 128MB for light tasks and careful kernel tuning, 512MB is a more realistic minimum since it lets you install and update. But for X it's flipped: you need 2G to install but closer to 4G or 8G to run a complete, but on the lean side, X11 system.<br> ><br> > Warner<br> >><br> >><br> <br> </blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>brandon s allbery kf8nh</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a></div></div></div></div></div> </blockquote></div></div>home | help
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