u-boot & ZFS

[ChrisO]

On Wed, Aug 18, 2021 at 12:26:11PM +0200, Lukasz Majewski wrote:
> Hi ChrisO,
> 
> > On Tue, Aug 17, 2021 at 08:35:14PM -0400, Tom Rini wrote:
> > > On Tue, Aug 17, 2021 at 06:03:10PM +0200, ChrisO wrote:
> > >   
> > > > Hi
> > > > 
> > > > I searched for u-boot ZFS references and all I found was several
> > > > years old, but I suppose u-boot can cope with ZFS. So, my
> > > > question is: is it possible to boot Linux from ZFS or at least
> > > > boot from let's say SD-card with ext4 FS and mount a ZFS volume
> > > > as root filesystem? I had a look at Armbian, installed all
> > > > needed, user-space and kernel modules. After booting from SD card
> > > > I can use ZFS on attached SATA SSD w/o any problem. I also see
> > > > ZFS libs and kernel modules in initrd,  so it looks like the
> > > > necessary things are there. Don't know where to start. I would be
> > > > very thankful for any help.  
> > > 
> > > The general easy answer is to have /boot that is separate from the
> > > rootfs and using a filesystem more commonly supported.
> > > 
> > > -- 
> > > Tom  
> > 
> > Sounds like: go away kid, play with your old toys ;-)
> > I was doing it the traditional way for long time, now wanted to try
> > something new. Isn't it how we progress? I came to this list hoping
> > to get an answer to my question. I know, most of you on this list
> > have more important things to do. But giving me some advice could
> > possibly result in me giving something back.
> > 
> 
> Similar question I saw on OpenEmbedded/Yocto ML recenly. The answer
> there was that "ZFS or ZOL is _not_ [*] commonly used on embedded
> systems, so no support was needed" 
> 
> If find this topic interesting, then the community will try to help
> when you provide any patches for review.
> 
> However, considering the above, it may be hard for any _exact_
> guidelines.
> 
> 
> Note:
> [*] - Personally, I didn't saw any usage of ZFS on embedded systems.
> 
> > Thanks,
> > Chris
> 
> 
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
> --
> 
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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Hallo Lukasz

My system in question is not an embeded one. I just stated to play with an Odroid-HC4 and Armbian.
It has two SATA connectors, boots from a SD card.
All computer I use which have more than one disk connected are set-up with software RAID and LVM on top of it.
ZFS has both build-in it's why I asked.
Currently I have on this HC4 two partitions on each disk, the smaller ones are in RAID1 and host root FS, the bigger ones are in a mirrored Zpool. It works OK, it would be nicer to have just one filesystem, though.

Still not sure, it can or cannot be done?

Thanks and regards,
Chris