From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [ANNOUNCE] mdadm-3.1 has been withdrawn Date: Mon, 09 Nov 2009 16:07:09 -0500 Message-ID: <4AF8847D.8030303@redhat.com> References: <19187.50708.551325.297625@notabene.brown> <4AF829B2.5090001@redhat.com> <4AF836F8.5040903@panix.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig86E569C25CBF68BE8EA183B5" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: Jon Nelson , linux-raid@vger.kernel.org List-Id: linux-raid.ids This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig86E569C25CBF68BE8EA183B5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 11/09/2009 11:51 AM, Mikael Abrahamsson wrote: > On Mon, 9 Nov 2009, Jon Nelson wrote: >=20 >> I've been using 1.1 for everything. What's the current wisdom >> regarding 1.0 vs 1.1 or 1.2? >> I used 1.1 because that's also where filesystem metadata usually goes >> and therefore one might hope that the presence of the md metadata >> would prevent accidental identification of a raid volume as containing= >> a filesystem. >=20 > I like 1.2 because if you happen to write an MBR or something to the > drive, you don't lose the superblock. Of course, I recently had a bug report that I ended closing out as NOTABUG because of this very ability. The person had arrays with 1.2 superblocks, and they went to add a new disk, and all the existing disks had a specific partition layout, so he copied that to the new disk, then tried to add the partition to the raid array. It kept returning "device too small for array". Then, upon inspection, we come to see he has a 1.2 superblock on the *entire* drive, which left the partition table intact, but the partition table is *pointless* because the array is on the whole disk devices. This sort of confusion is bad. So, while I could see making it 1.2 for partitions (so that boot sectors won't overwrite the superblock), I wouldn't make it 1.2 for whole disk devices, and in fact it might be wise to refuse to create 1.2 superblocks on whole disk devices. Just a thought. > With 1.2 I can also take the drive from a 3ware hw-raid (single drive i= n > 3ware bios) and put in a non-3ware (because the 3ware stores the > superblock at the end, so when you put it in a non-3ware the end has no= w > changed). 1.1 should work just as well for this. --=20 Doug Ledford GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband --------------enig86E569C25CBF68BE8EA183B5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkr4hH0ACgkQg6WylM+/8ZTOAwCeI3f7VENsGJid4JsgdL7y3Lha OYEAniF6DxATYcP+15j+OnGEcllVyMn6 =fhHp -----END PGP SIGNATURE----- --------------enig86E569C25CBF68BE8EA183B5--