From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: RAID1 assembled broken array Date: Fri, 25 Sep 2009 18:12:07 +1000 Message-ID: <19132.31575.349988.442763@notabene.brown> References: <9F2F4760-DF0C-4416-89AC-C689177AD4ED@redhat.com> <65549e07fd6559855af68b60783213c3.squirrel@neil.brown.name> <20090917082528.GO5174@skl-net.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Andre Noll on Thursday September 17 Sender: linux-raid-owner@vger.kernel.org To: Andre Noll Cc: Doug Ledford , Matthias Urlichs , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thursday September 17, maan@systemlinux.org wrote: > On 07:01, NeilBrown wrote: > > > Wrong lesson. The correct lesson to gather from this is to prefer > > > version 1.1 or 1.2 superblocks wherever possible. Superblocks at the > > > beginning of the device disappear when there is no partition table, > > > superblocks at the end can be confused for superblocks belonging to > > > the whole device when there is no partition table. > > > > 1.0 also protects from this problem. The 1.x metadata stores the > > offset of the superblock from the start of the device. That will appear > > to be wrong if you find a partition-superblock when reading from a > > whole-device, so mdadm will reject the device as not having a valid > > superblock. > > BTW: Why are new arrays still created with 0.90 metadata format by > default? Because I'm a chicken.... I guess it probably is time ... but to we make the default 1.0, which is compatible with people's expectations, to 1.1 which is generally a safer approach (you cannot mount a bare device by mistake). Of course a distro can import their own default using the CREATE line in mdadm.conf. NeilBrown