RBPI3B+ FreeBSD 12 ZFS

[Bernd Walter]

On Fri, Feb 22, 2019 at 09:49:24AM -0800, Rodney W. Grimes wrote:
> > 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 at 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.

I did USB boot tests with a RPI3B+.
It is a mess.
With many devices it won't boot at all, with some it randomly fails.
On the fail side there also had been a few SanDisk USB sticks.
Only a few seemed to work fine, but the fact that some randomly fail
to boot make me less confidend if a media really works.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.