ZFS root on MB Intel S3420GP

[Jeremy Chadwick]

On Sun, Apr 17, 2011 at 08:31:35PM +0400, Lystopad Olexandr wrote:
> On Sun, Apr 17, 2011 at 07:21:35AM -0700
> freebsd at jdc.parodius.com wrote about "Re: ZFS root on MB Intel S3420GP":
> > On Sun, Apr 17, 2011 at 04:32:32PM +0400, Lystopad Olexandr wrote:
> > > I have this hardware:
> > > 
> > > smbios.system.maker="Intel Corporation"
> > > smbios.system.product="S3420GP"
> > > 
> > > with 4G ram and 4x WD 500G drives.
> > > 
> > > I try both raids in the bios, in both cases i try raid 10.
> > > I.e. I have 1Tb ar0 device.
> > 
> > I strongly urge you to remove use of Intel RST[1].  It's been confirmed
> > many times over[2] that FreeBSD's support for it is broken in many
> > regards.  You are putting your data at extreme/great risk using it.
> > Something as simple as a single-disk failure could result in the
> > *entire* loss of your array.  You will need to read the PRs listed at
> > Wikipedia slowly, and in full to understand the nature of the problem.
> > Do not skim them.
> > 
> > I cannot stress the importance of this enough.  This is not a joke nor
> > is it overblown.  I recommend you rely on ZFS entirely, and run your
> > SATA controller in AHCI mode instead.  My personal recommendation would
> > be to use UFS for your root filesystem (or even gmirror) and use ZFS for
> > the rest.
> 
> Jeremy, thank you very much!
> 
> I remove intel raids and move to ahci already.
> I install freebsd 8.2-amd64 on that box and about to make gmirror
> with 4 disks. :-)
> 
> Is it possible to remote migrate to zfs? I have access to this
> server remotely, and do not have local access. This server with 4
> disks, and I can do anything with 3 of disks. Now there installed
> 8.2-amd64 on ad4.

An honest and simple answer: I don't know.  I don't use ZFS for my root
filesystems on any server I manage, only as a secondary filesystem that
gets used for things like /home.  I do remote installations of FreeBSD
on occasion (PXE boot + all access via serial console), but I don't do
ZFS-on-root.

> > With regards to AHCI mode: Most of us strongly advocate use of ahci.ko
> > (not ataahci.ko; they differ), which does SATA<->CAM translation.  You
> > also gain NCQ capability using this.  Be aware your disks will appear as
> > "adaX" (not a typo), and you will use "camcontrol" (rather than
> > "atacontrol") to maintain them.  Utilities like smartmontools do work
> > with this.  Many of us (users and developers) have been using ahci.ko
> > reliably for 1-2 years now.
> 
> Simply add ahci_load="YES" in loader.conf? Or something else?

Correct.

I tend to do the following from the very beginning of a new FreeBSD box
installation, however:

- Boot FreeBSD installation medium (PXE, CD, USB, whatever)
- At beastie menu, escape to loader prompt and do "load ahci" then
  "boot"
- Install FreeBSD like usual, creating slices/partitions on adaX disks
  like normal, etc...
- When the system reboots, at the beastie prompt, make sure to escape to
  loader and do "load ahci" then "boot" again.
- Once the system is finally up, edit /boot/loader.conf to add
  ahci_load="yes".

I wish one could easily (read: across serial console/remote/PXE) add
stuff to /boot/loader.conf *prior* to the completion of the FreeBSD
installation.  One can edit /etc/ttys from within sysinstall, why not
/boot/loader.conf?  The emergency terminal isn't accessible if you're
doing things via serial console, so dropping to that to do some magic
won't work.

> > > After reading http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/RAIDZ1 I
> > > try to install FreeBSD on this box, but I change ad0..ad1.. to my
> > > ar0 device. I try to have zfs on intel raid10.
> > > 
> > > All commands run successfully, but after reboot I have:
> > > 
> > > gptzfsboot no zfs pools located: can't boot
> > > 
> > > What mistake I made? 
> > > 
> > > What best solution with my hardware exist?
> > 
> > I imagine what you're trying to accomplish won't work given that the
> > disk geometry and other mechanics are completely lost given use of
> > Intel RST, and *especially* with regards to the boot sequence.
> > 
> > Furthermore, the bootstraps you're using imply use of GPT; did you
> > configure your setup using GPT?  I'm guessing not.
> 
> I make all steps in url in first my mail.
> 
> Am I wrong?

The default FreeBSD installer/labeller/partitioner doesn't use GPT.  I
do not use GPT myself either.  If you need GPT, lots of others here can
help you with that part.  All I know is that you should not confuse the
term "GPT" with "gpart".  :-)

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.               PGP 4BD6C0CB |