From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miles Fidelman Subject: Re: possibly silly question (raid failover) Date: Tue, 01 Nov 2011 16:13:26 -0400 Message-ID: <4EB052E6.4050400@meetinghouse.net> References: <4EAF3F78.5060900@meetinghouse.net> <4EAFEE95.6070608@meetinghouse.net> <4EAFF636.6060904@anonymous.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids David Brown wrote: > > No, md RAID10 does /not/ offer more redundancy than RAID1. You are > right that md RAID10 offers more than RAID1 (or traditional RAID0 over > RAID1 sets) - but it is a convenience and performance benefit, not a > redundancy benefit. In particular, it lets you build RAID10 from any > number of disks, not just two. And it lets you stripe over all disks, > improving performance for some loads (though not /all/ loads - if you > have lots of concurrent small reads, you may be faster using plain > RAID1). wasn't suggesting that it does - just that it does things differently than normal raid 1+0 - for example, by doing mirroring and striping as a unitary operation, it works across odd number of drives - it also (I think) allows for more than 2 copies of a block (not completely clear how many copies of a block would be made if you specified a 16 drive array) - sort of what I'm wondering here -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra