[mythtv-users] RAID versus Drobo

Eric Robinson ryunokokoro at gmail.com
Sun Sep 9 16:15:19 UTC 2007

John Drescher wrote:
>> As I see it, the SATA based RAID would be nice for it's simplicity and
>> speed.  The motherboard I will be using should support dual RAID-5
>> setups offering me tons of space with 750GB drives.  It may prove more
>> costly to run, however, if the drives don't spin-down when not in use.
> Unless you paid $500 or more from the motherboard it is very unlikely
> that it supports hardware raid5. Most motherboards use fake raid
> (proprietary software raid) which is in most cases worse than the
> software raid that is built in to windows. The only real advantage to
> fake raid is that you can run windows and linux on the same box and
> they can both use your drives.
>> The Drobo is interesting because it is hot-swappable and expandable.
> Linux software raid is expandable and  likely that your drives are
> also hot swappable as I hot swap drives at work every once and a while
> and I have been doing so since 2004. Although I guess the the key here
> with the Drobo is that its simple to use.
> ...
> I also missed the fact that although there is a hard to find dmraid
> fake raid5 driver out there in source code form it is not yet in any
> kernel that I have seen.  So basically it will be difficult to make
> use of fake raid 5 with linux.
> John
Thanks for the rather informative responses.  Helpful stuff!

I didn't mention hardware RAID-5 specifically but your point helped
clarify things quite a bit.  I would most definitely be doing a software
[fake] RAID-5 setup in Linux.  Some digging revealed a few links:


It looks like linux based RAID-5 using mdadm is the way to go.  The
features and such outlined in the first link make it a rather appealing
proposition.  And, at least as of kernel 2.6.17, RAID-5 arrays appear to
be relatively easy to expand.  This makes the choice a bit simpler.

While Drobo wins in ease-of-use, fake RAID-5 now appears to win in terms
of expandability (the Motherboard I'm eying has 10x SATA connections
onboard).  I feel like I could be missing something.  Does that all
sound alright?

I guess my question about the Drobo really boils down to the
throughput.  Is USB 2.0 fast enough for HD content storage in a Myth
setup with multiple Frontends?

- Eric

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