<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd"><html><head><meta name="qrichtext" content="1" /><style type="text/css">p, li { white-space: pre-wrap; }</style></head><body style=" font-family:'Sans Serif'; font-size:10pt; font-weight:400; font-style:normal;">On Monday 15 June 2009 21:49:20 Hadley Rich wrote:<br>
> On Mon, 2009-06-15 at 21:38 +1200, Jim Cheetham wrote:<br>
> > If you lose a second drive while one drive is out of action ... you<br>
> > lose data. Gone.<br>
><br>
> Same as your two disk RAID1.<br>
><br>
> > RAID5 doesn't give enough protection for your data, especially given<br>
> > the relative costs of media today. It has horrible failure modes,<br>
> > especially given that we don't know about drive health (most drive try<br>
> > self-healing without telling the OS that it's happening ... only<br>
> > informsingthe OS when a fatal error has occured). For big systems,<br>
> > RAID5 does not deliver decent performance (unlikely to be important<br>
> > for MythTV usages)<br>
><br>
> Disks fail and notify how they do, no matter what arrangement they are<br>
> in.<br>
><br>
> RAID5 has enough performance for most things, is cheaper and is easy to<br>
> grow.<br>
><br>
> They both still have their uses.<br>
><br>
> hads<br>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"><br></p>I think Jim has a point. All my drives were reporting A-OK through SMART, and the failed drive still reports OK - it just throws I/O errors and locks up if you try to write to it. I have read a couple of research papers which have come to the conclusion that SMART is almost useless for predicting when a drive will actually fail, and (from memory) around half of drives fail without any prior warning.<br>
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