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On 9/21/2011 16:54, Travis Tabbal wrote:<br>
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<div class="gmail_quote">On Wed, Sep 21, 2011 at 2:09 PM, linux
guy <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:linuxguy123@gmail.com">linuxguy123@gmail.com</a>></span>
wrote:<br>
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<div>I'm not sure what to say. I haven't had a HD fail in
the last 10 years. I'm not sure why I would need a RAID
setup that would tolerate multiple drive failures.<br>
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<br>
The issue with RAID5 is that you are putting everything into a
single array. If you have two drives fail, you lose everything,
with no chance of recovery of any of it. If you go with multiple
RAID1 arrays, you are really not losing all that much storage,
especially if you use the cost of the RAID card to instead buy more
drives, and one array failure means you're only losing the contents
of that one array.<br>
<br>
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<div>And you can get I/O bound very fast with recordings and
playback in a myth system using RAID, particularly a small
RAID5 like you are talking about. Performance of the array is
about equal to a single drive, add in all the seeks you need
to keep up with and your available I/O falls off fast. Using
single drives in storage groups is a better solution, IMO. If
you really must archive the TV shows, I would use 2+ drives
for recordings in a Myth SG, then copy the recordings off to a
large, slower, array later.<br>
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<br>
That's what I end up doing. Recordings go to a smattering of
individual drives from 300GB to 2TB, while the commercial-clipped
archive is on a 5.25TB hardware RAID6 array.<br>
<br>
Another interesting option would be using a ZFS volume, with
multiple drives as independent non-redundant zvols, and then marking
your recordings as needing two copies. Files are not striped across
multiple drives. Read performance is exactly that of independent
drives, and write performance is half that. If you lose a single
drive, ZFS makes a second copy of the lost files on one of the other
drives. If you two drives, you only lose those files that only
existed on those two drives.<br>
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