From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Brown <david@westcontrol.com>
Subject: Re: What's the typical RAID10 setup?
Date: Tue, 01 Feb 2011 11:05:29 +0100
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On 31/01/2011 23:38, Phillip Susi wrote:
> On 1/31/2011 5:08 PM, Jon Nelson wrote:
>> I operate (and have done so for a long time) a raid10,f2 on two drives.
>> What makes you think it wants at least 3?
>
> Neat, I thought I tried that the other day and it complained that raid 5
> and 6 ( sic ) need at least 3 drives.  Seemed like it was just a bug or
> oversight.

raid5 needs at least 3 disks to make sense (raid5 with 2 disks is the 
same as raid1), while raid6 needs at least 4 disks.  But mdadm raid10 
needs only two disks.