Fwd: Possible (or smart) to put freebsd-boot on USB stick for root-on-ZFS?

Arthur Chance freebsd at qeng-ho.org
Tue Mar 24 11:58:02 UTC 2015

On 24/03/2015 09:08, Jason Birch wrote:
> On Tue, Mar 24, 2015 at 7:56 PM, Mehmet Erol Sanliturk
> <m.e.sanliturk at gmail.com> wrote:
>> On Tue, Mar 24, 2015 at 1:29 AM, Polytropon <freebsd at edvax.de> wrote:
>>> On Tue, 24 Mar 2015 00:49:46 -0700, Mehmet Erol Sanliturk wrote:
> While I appreciate the discussion this has generated, it's not quite
> related to the questions I had around the freebsd-boot partition alone
> being on some removable media, and I'd like to try and steer the
> discussion back in that direction for my benefit (obviously ;)) and
> for the benefit of anyone trawling the lists looking for a similar
> answer.
> For the record, this will be for a reasonably large ZFS file server,
> and so having things like the home directories live on the larger ZFS
> volume (and not the mirrored SSDs) is something I'll probably be
> doing. However, it's more about the partitioning and device
> arrangement once the machine has booted, and that's not quite what I'm
> having difficulties understanding.
> I will, of course, be trying these things out myself on the weekend.
> But I'm also hoping for some experiences from those who have tried, or
> who know the innards of freebsd-boot enough to know without trying,
> such a set up.

Sounds like you might want to take a look at the FreeNAS web site, as 
that's the sort of thing it does. I've not used it myself, but when 
configuring a new file server I picked up various ideas from the forums 
there, and one thing I noted in passing was that FreeNAS is often run 
from a memory stick, leaving the main disks entirely free for data 
pools. I.e. both the boot partition and / are on the memstick.

You don't need all of the root partition to boot the kernel, just /boot, 
but I don't know whether the gpt*boot programs require /boot to be on 
the same drive as they are on. I suspect it's highly likely as the boot 
programs are usually fairly simple. This would mean you'd need two 
partitions on the memstick, for the boot code and /boot, and suitable 
entries in /boot/loader.conf

> Thanks, and sorry for being a downer,

Quite understandable. Discussions here are often enlightening, or at 
least amusing, to the general reader, but if you want a specific 
question answered they can be infuriating. BT,DT.

Those who do not learn from computing history are doomed to

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