From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rechenberg, Andrew" Subject: Re: RAID 10 and Persistent Superblock Date: Fri, 31 Oct 2003 12:33:59 -0500 Sender: linux-raid-owner@vger.kernel.org Message-ID: <1067621639.6601.5.camel@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: To: AndyLiebman@aol.com Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids I have a 56-disk RAID10 and I have persistent superblocks on all of the md devices. I believe the RAID code is smart enough to know that a superblock already exists and places a new superblock 'before' the other one. So the end of your disk should look like the following drawing: -----------------------------------| DATA | RAID0SB | RAID1SB | -----------------------------------| When I created my RAID10 array, I believe that the superblocks were created in this fashion. Any RAID guru care to comment? Regards, Andy. On Fri, 2003-10-31 at 10:23, AndyLiebman@aol.com wrote: > A "simple" question regarding RAID 10. When I make a RAID 0 on top of three > RAID 1 arrays, should I use "persistent superblock = 1" in that top level > array? Won't that confuse the RAID software by putting two different UUIDs on the > drives -- one for the RAID 1 arrays and one for the RAID 0 array? > > As long as I have UUIDs for the three lower level RAID 1 arrays, I should be > able to start those arrays with mdadm even if my device ids change. > > Then shouldn't I be able to start the top level array without a UUID -- just > by referring to the mdX numbers? In other words, if md0, md1, md2 start, there > shouldn't be any confusion about which are the correct devices to start up > md3. Or am I missing something? > > Appreciate your answers. > > Andy Liebman > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Regards, Andrew Rechenberg Infrastructure Team, Sherman Financial Group