[mythtv-users] MythTV on Fedora 10 LVM backup/restore

Brian Wood beww at beww.org
Wed Apr 8 17:46:45 UTC 2009


On Wednesday 08 April 2009 11:37:18 Mike Perkins wrote:
> John Drescher wrote:
> >> Incidentally, you mentioned you were trying to get BIOS RAID working.
> >> Most of the time these aren't worth the trouble.  Most of them are
> >> actually software RAID, implemented in the Windows driver, with some
> >> minimal BIOS support for booting from the RAID array -- sometimes
> >> referred to as "fakeraid."  They don't really get you anything that
> >> Linux md RAID doesn't.
> >
> > Anything good that is. They are significantly less reliable and will
> > provide many headaches.
>
> - And could cause you total loss of data if your motherboard dies, and you
> can't replace it with one that has the exact same bios with the exact same
> software revision, running on the exact same hardware chips as your old
> one.
>
> Unless you're running raid purely for the performance (ie not for
> security), *don't* use the bios raid, do it in software.

Yeah, that sort of "RAID" is just something they can add to a mobo for very 
little cost, and get a marketing tool, not anything that actually helps 
anyone.

Most will also only do "RAID" 0 and 1, and sometimes JBOD, never RAID5 or 
anything useful like that.

I agree Linux software RAID is far better, in some cases better than a 
hardware RAID controller (some of which only work with specific drives, which 
can become unobtainable). The CPU overhead for software RAID is negligible 
these days (it was 10 years ago), so it's definitely the way to go unless you 
have a specific reason (and budget) for true hardware RAID.

I don't think the "fake" RAID has any better performance than Linux software 
RAID, but most of the fakes use Windows-only drivers, so it's hard to tell.

All RAID is really software, it's just a question of where the software is 
running (on your CPU or an add-in card).

-- 
beww
beww at beww.org


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