Quoting Clifton Royston <[EMAIL PROTECTED]>:
On Wed, Jan 02, 2008 at 08:47:43AM -0800, Chris H. wrote:
Quoting John Nielsen <[EMAIL PROTECTED]>:
>I'm not sure I remember everything from earlier in this thread so I
>don't know if it's relevant, BUT you can't boot from a gstripe volume
>(or from a gconcat one AFAIK). Inferring from your fstab example
>below it doesn't sound like you intend to but I just wanted to be
>sure.
Are you sure? I read that using gmirror requires /kernel to be located
in the /boot slice and everything else (all other slices) can be mirrored
safely. But in all my reading (man pages, FBSD handbook, asstd articles)
I haven't seen anything indicating booting wasn't possible from a gstripe
volume.
Your current idea is backwards; you can boot from entirely mirrored
drives (i.e. RAID1) and I've been doing it since 5.3, but AFAIK it is
impossible to boot from a striped drive and I suspect will remain so
for a long time.
One way to visualize this is to recognize that because the gmirror
information is stored at the very end of the lower-level GEOM object,
each of the raw drives in the mirrored set appears to be an perfectly
normal drive when reading it from its beginning; thus it is possible to
simply read it as a normal device during the earlier stages of boot
until GEOM and gmirror loads. With striping, however, the logical
content is spread out across multiple drives, so any one drive you try
to boot from has only 1/Nth of the relevant sectors.
Indeed, and thank you for pointing out the obvious to me. :)
I was almost immediately reminded of that after posting. :P
But really, I appreciate your taking the time to /enlighten/ me.
It /does/ help.
Given the /wealth/ of information afforded to me here on the list,
after proposing my intentions. It quickly occurred to me that I
had developed quite a few misconceptions about GEOM and friends,
and that I should have taken just a bit more time before leaping.
In the final analysis, I think it would be /far/ more efficient if
I simply blanked my current disk, and simply laid it out as I ultimately
want it. Then simply unarc the root folders to their desired destinations
from the most recent backups. Which kind of makes this thread a loop.
As my initial question was why wasn't gMIRROR part of sysinstall.
It's funny, I've spent over 2 decades running *BSD, and yet I never
really spent much time obtaining intimate knowledge about the disk
"construction". Oh, it's not that I know nothing about it. But rather,
that once I determined the ultimate layout for my needs, I simply
let sysinstall handle it. So other than needing to add disks and move/
re-create slices, I was done. But as I now revisit it, I discover I
should probably spend a little more time acquainting myself with it. :)
Thanks again for taking the time to respond. I appreciate it.
Chris
Does this help?
-- Clifton
--
Clifton Royston -- [EMAIL PROTECTED] / [EMAIL PROTECTED]
President - I and I Computing * http://www.iandicomputing.com/
Custom programming, network design, systems and network consulting services
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