Bootstrapping Raid 5 w/GEOM

[Norberto Meijome]

Stijn Hoop wrote:
> On Thu, Jul 21, 2005 at 05:11:18PM +1000, Norberto Meijome wrote:
> 

>>
>>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 
>>suggestions.

> 
> 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.

Would the same be true (not possible to boot) for a RAID 1 + 0 with GEOM?

> 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.

right - so that's why I couldnt find any reference to this anywhere :)


> 
> 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).

I guess I could create a boot slice in 2 of the drives, mirror that with 
gmirror and use that to boot. Then RAID-5 the rest of the drives (minus 
the size of the boot partition in the other 2 drives of course).

cheers,
B