RAID 0 is a striped set, no parity.<br>RAID 1 is a mirrored set.<br><br>So RAID60 would be two RAID 6 arrays striped together.<br><br>RAID61 would be two mirrored RAID 6 arrays... I could see maybe why you would strip two RAID 6 arrays to increase performance, but that would be incredibly costly and I would say complete overkill. If you need redundancy and speed is a high priority, you might as well do RAID10, a stripped set of mirrored drives. However, if you a have a limited number of drives and needed the most storage size by reducing the ratio of parity drives and disk I/O performance isn't too important then RAID 5/6 is your answer.
<br><br><div><span class="gmail_quote">On 6/5/07, <b class="gmail_sendername">Phil Thayer</b> <<a href="mailto:phil.thayer@vitalsite.com">phil.thayer@vitalsite.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
If you do that you need to make sure that the controller will support<br>RAID 6 or RAID ADG. This is simply a RAID 5 with an additional parity<br>disk implemented. This reduces the risk of failure of the entire RAID<br>
if a single disk fails. The RAID will simply function as if it were a<br>RAID 5 until the failed disk is physically replaced and the RAID 6 or<br>RAID ADG is rebuilt.<br><br>As an alternative, if you have a controller that does not have RAID 6 or
<br>RAID ADG, then you can use RAID 5 with a spare disk set aside for use as<br>a spareset in case of a failure. This does not eliminate the risk in<br>case of a single disk failure but it reduces it to the time required to
<br>rebuild the RAID using the spareset as opposed to the time it takes to<br>physically replace a drive in a degraded RAID 5. If you suffer a second<br>disk drive failure during the time that the RAID 5 is rebuilding after
<br>the first disk drive failure, then you will loose your entire RAID.<br><br>The ultimate high availability configuration would be RAID 60+. This<br>would be two RAID 6 with their own sparesets assigned, mirrored to each
<br>other. However, be prepared to loose a larger percentage of your raw<br>disk drive space. You will loose the equivalent of:<br><br>Two disk drives for each RAID 6 used<br>Two disk drives for each RAID 6 for redundant sparesets
<br>One raid 6 with the mirroring<br><br>I really don't expect that you would build something like that for a<br>home server but I figured I would throw all that out there just in case<br>you had more money that you know what to do with and want to make sure
<br>the data on your server is safe from failure.<br><br>Phil<br><br>> -----Original Message-----<br>> From: <a href="mailto:kclug-bounces@kclug.org">kclug-bounces@kclug.org</a><br>> [mailto:<a href="mailto:kclug-bounces@kclug.org">
kclug-bounces@kclug.org</a>] On Behalf Of Luke-Jr<br>> Sent: Tuesday, June 05, 2007 9:20 AM<br>> To: <a href="mailto:kclug@kclug.org">kclug@kclug.org</a><br>> Subject: Re: SATA PT2<br>><br>> On Tuesday 05 June 2007 09:11, Phil Thayer wrote:
<br>> > Not to mention that with the recent SATA drive sizes to get<br>> 1TB of SATA<br>> > would only take 2 drive. However, if you want to use a<br>> multi-channel<br>> > SATA controller with raid you will want to use smaller
<br>> drives (like 4 x<br>> > 300 or 8 X 250) so you don't loose too much capacity to parity.<br>><br>> With 8 drives, I'd probably want to make 2 parity for a<br>> server... As unlikely<br>> as it is for 2 drives to fail at once, that chance does
<br>> increase with # of<br>> drives.<br>> _______________________________________________<br>> Kclug mailing list<br>> <a href="mailto:Kclug@kclug.org">Kclug@kclug.org</a><br>> <a href="http://kclug.org/mailman/listinfo/kclug">
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http://kclug.org/mailman/listinfo/kclug</a><br></blockquote></div><br>