From mboxrd@z Thu Jan  1 00:00:00 1970
From: Phillip Susi <psusi@cfl.rr.com>
Subject: Re: What's the typical RAID10 setup?
Date: Mon, 31 Jan 2011 16:59:28 -0500
Message-ID: <4D4730C0.8080900@cfl.rr.com>
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To: Stan Hoeppner <stan@hardwarefreak.com>
Cc: Denis <denismpa@gmail.com>, Roberto Spadim <roberto@spadim.com.br>, Linux-RAID <linux-raid@vger.kernel.org>
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On 1/31/2011 3:23 PM, Stan Hoeppner wrote:
>> Raid 10 is not raid 1+0.  Raid 10 defaults to having 2 duplicate copies,
> 
> Yes, actually, they are two names for the same RAID level.

No, they are not.  See the mdadm man page.  Raid10 can operate on 3
drives, raid1+0 can not.  In theory a raid10 could be done on two disks
though mdadm seems to want at least 3.

> This is absolutely not correct.  In a 10 disk RAID 10 array, exactly 5 disks can
> fail, as long as no two are in the same mirror pair, and the array will continue
> to function, with little or no performance degradation.

That is a raid 0+1, not raid10.

> Where are you getting your information?  Pretty much everything you stated is
> wrong...

The mdadm man page.