Bootstrapping Raid 5 w/GEOM
stijn at win.tue.nl
Thu Jul 21 12:40:52 GMT 2005
On Thu, Jul 21, 2005 at 05:11:18PM +1000, Norberto Meijome wrote:
> Hi all,
> I have a box with 4 x 120 GB EIDE drives which I want to convert to
> FreeBSD 5.4 ( it's an old SNAP 4500 from Snap Appliance, now owned by
> Adaptec, running a custom build of Linux)
> I want to setup software Raid 5 , and I want it to affect ALL
> partitions, including / (so if any one of the drives fails, it will
> still boot up properly). I am planning on using GEOM, but open to
> I've been searching and cant find any pointers on how to set this up
> properly. I've been reading http://people.freebsd.org/~rse/mirror/ , but
> this is works for RAID 1.
> Could anyone offer any insights / ideas / pointers (or step by step if
> you so feel inclined to :-) ) on how to set this up?
I don't think it's possible -- the loader doesn't know about the mirror
even in a mirrored / setup; it justs treats one of the disks of the mirror
as 'the boot disk'. It's not until the kernel is loaded that gvinum RAID-5
can do something.
So, in your case, the loader would read random RAID-5 data instead of
a kernel and refuse to boot.
IE, it's not possible until someone writes a RAID-5 capable loader.
I would advise you to either use gmirror for booting, or define a few
gvinum mirror plexes (it is possible to boot from a mirrored gvinum
setup although it's tricky to get right).
Help Wanted: Telepath. You know where to apply.
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