[mythtv-users] Recording directly to RAID

Blammo blammo.doh at gmail.com
Mon Jul 30 05:16:15 UTC 2012


Since this thread seems to have wandered off a bit, I'll reply to the
original poster.

On Fri, Jul 27, 2012 at 11:27 AM, David Engel <david at istwok.net> wrote:
> Is anyone recording directly to RAID?  If so, what type/size, how many
> simultaneous recordings and how well does it work?

Yes, I made the jump to HWRaid5 a long time ago on my Mythbackend, and
haven't looked back.

I originally played with SDraid, but left that behind due to IO issues
and stability. I started with HDRaid, with a 3ware 9500S-12 with 6x160
SATA drives. With proper tuning (elevator=deadline, xfs stripe/stride)
I was able to do 6 SD recordings plus realtime commercial flagging and
never drop/glitch recordings. Moved to 12x160gig drives, then later
12x500GB drives, then to 12x1GB drives, 2 HDHomerun, all with no
issues.

Next jump was to 12x2TB seagate green drives, and an ARECA card (I
wanted RAID6, and  the out-of-band RAID management via the ethernet
port on the card). I would have shifted to ESXi, had it been able to
handle >2TB volumes. Instead I moved to ProxMox using KVM. I
virtualized the old backend, and exported the raid array via NFS to
the VM. Knock on wood, but I haven't lost a single 2TB drive in 2+
years.

I'm now up to 8 tuners, and I with all 8 going, realtime commercial
flagging, two frontends, and misc samba use, the raid array purrs
along with no issues, little-no io-wait. (The olympics are giving it a
good workout). I recently converted mythbackend to openVZ container,
and it's running better than ever. (To be fair, the machine is 2 x
quad-core opteron, with 32GB of ram, on a tyan server motherboard..
but CnQ works great, and the power-footprint is about 150W mostly
idle, which is amazing considering the drives/ram/etc)

So short version, yes, Raid is usable, possible, and worth the time,
cost, and effort in my opinion.


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