[mythtv-users] Killer system or overkill?
crunchyfrog at charter.net
Tue Dec 13 14:02:29 EST 2005
Grant Horning wrote:
> Let me clarify...
> Software RAID 5 will consume approx 20% cpu under a heavy I/O
> load. The disk performance will be very good but you must remember that
> cpu time is also very important. With dual cores, software raid 5 won't
> be a problem at all. With a single core, I would be worried about maxing
> out the cpu. You can see some benchmarks at
> Also, don't worry about the onboard raid chip. You wont be using it
> anyway. Linux has its own software raid. Try 'man md'.
Thanks. I said "software RAID" (and meant "md") so I'm not sure where
anyone got the idea that I was considering on-board RAID. I'm not.
I can't imagine why disk performance would be an issue. A 10000 RPM
disk used as a daily write cache surely is unnecessary -- even at HDTV
rates this isn't a huge amount of bandwidth by modern disk drive
standards. I'm considering RAID5 so that losing a hard disk won't be
fatal to the video library.
> My advice for a kick-ass system that will do more than just let you
> watch HDTV.
> Get dual cores
> Get 2GB ram (see benchmarks)
> Use software raid 5
> Get a case with great airflow + lots of power
Pretty much what I was considering except for RAM. I'll look at the
benchmarks, though; RAM's not all that expensive.
> I'm not sure if JFS or XFS perform the same as EXT3 or Reiser under RAID
> 5. That might be worth looking into.
Unless there's a good reason not to, I'll use XFS. I strongly prefer it
to ext3 for mythtv recordings.
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