Date: Fri, 22 Feb 2019 09:49:24 -0800 (PST) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: Ian Lepore <ian@freebsd.org> Cc: Stefan Parvu <sparvu@kronometrix.org>, freebsd-arm@freebsd.org Subject: Re: RBPI3B+ FreeBSD 12 ZFS Message-ID: <201902221749.x1MHnO8R026440@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <facfaeae8cef0351b91194ed0b7e30345139e668.camel@freebsd.org>
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> On Fri, 2019-02-22 at 17:38 +0200, Stefan Parvu wrote: > > I know ZFS would need a decent amount of RAM to start with. So for > > such low sized > > SBC systems, like Raspberry PI having ZFS for root might be no go. > > > > What I meant was: how complicated would be right now for FreeBSD 12 > > to have an > > ARM64 RBPI3B+ image image which could use ZFS to boot from a SD Card. > > > > Stefan Parvu > > sparvu@kronometrix.org > > > > > > People have run a 512MB beaglebone with zfs on sdcard. It surely wasn't > high performance, and it reported needed some hand-tuning to run at > all, but it worked. you can run zfs based systems in a very small amount of memory, including on FreeBSD i386 IF you limit the size of the arc cache by vfs.zfs.arc_max= in /boot/loader.conf for small memory systems I recommend no more than 50% of memory. I have run ZFS on 128MB systems, and run a VM that is zfs root in 1G on a daily basis. So memory is NOT your issue with doing this on a RPI3B+ > > There's a lot of mythology about sdcards and what they can and can't > do, and how supposedly fragile they are. It's all a bunch of noise you > can safely ignore. They're slow, but they're plenty reliable. I agree. Also you should be able to boot the RPI3B+ from USB, and that would be a far better solution, USB can have issues though too, but my experience is it is a slight step better than sdcard slowness. > -- Ian > > > On 22 Feb 2019, at 17.23, Karl Denninger <karl@denninger.net> > > > wrote: > > > > > > On 2/22/2019 09:07, Stefan Parvu wrote: > > > > Hi, > > > > > > > > Just curious, would ZFS work on a RBPI3B+ board with 1 GB RAM > > > > only > > > > using FreeBSD 12 STABLE ? the hardware is 64bit but would it boot > > > > on > > > > 1 GB RAM for its own ARC internal operations ? > > > > > > > > Thanks, > > > > > > > > Stefan Parvu > > > > sparvu@kronometrix.org > > > > > > Are you talking about attempting to mount root off a ZFS filesystem > > > on > > > the SD card or booting it as usual and then loading zfs once > > > running > > > (e.g. to talk to a USB-attached disk)? > > > > > > I think you'll find that while it might run it's a very bad idea > > > for a > > > whole host of reasons; what purpose do you have in doing this? > > > > > > -- > > > Karl Denninger > > > karl@denninger.net <mailto:karl@denninger.net> > > > /The Market Ticker/ > > > /[S/MIME encrypted email preferred]/ -- Rod Grimes rgrimes@freebsd.org
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