From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: Time to deprecate old RAID formats? Date: Sat, 20 Oct 2007 10:24:36 -0400 Message-ID: <1192890276.1666.126.camel@firewall.xsintricity.com> References: <18200.49267.763509.924873@stoffel.org> <18200.53593.687483.120827@stoffel.org> <1192810534.1666.68.camel@firewall.xsintricity.com> <471A0C02.4030407@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-9l8I9BRvSR2PD70rtTqf" Return-path: In-Reply-To: <471A0C02.4030407@msgid.tls.msk.ru> Sender: linux-raid-owner@vger.kernel.org To: Michael Tokarev Cc: John Stoffel , Justin Piszcz , linux-raid@vger.kernel.org List-Id: linux-raid.ids --=-9l8I9BRvSR2PD70rtTqf Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Sat, 2007-10-20 at 18:09 +0400, Michael Tokarev wrote: > Doug Ledford wrote: > [] > > 1.0, 1.1, and 1.2 are the same format, just in different positions on > > the disk. Of the three, the 1.1 format is the safest to use since it > > won't allow you to accidentally have some sort of metadata between the > > beginning of the disk and the raid superblock (such as an lvm2 > > superblock), and hence whenever the raid array isn't up, you won't be > > able to accidentally mount the lvm2 volumes, filesystem, etc. (In wors= e > > case situations, I've seen lvm2 find a superblock on one RAID1 array > > member when the RAID1 array was down, the system came up, you used the > > system, the two copies of the raid array were made drastically > > inconsistent, then at the next reboot, the situation that prevented the > > RAID1 from starting was resolved, and it never know it failed to start > > last time, and the two inconsistent members we put back into a clean > > array). So, deprecating any of these is not really helpful. And you > > need to keep the old 0.90 format around for back compatibility with > > thousands of existing raid arrays. >=20 > Well, I strongly, completely disagree. You described a real-world > situation, and that's unfortunate, BUT: for at least raid1, there ARE > cases, pretty valid ones, when one NEEDS to mount the filesystem without > bringing up raid. Raid1 allows that. Name one. --=20 Doug Ledford GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband --=-9l8I9BRvSR2PD70rtTqf Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQBHGg+jTzP9PM7pjw8RAj6zAJ9xysJnHBnE/RltYOif7cdgIUXYyQCbB7vF VWXLoCgelf1ZICPQRkWiT7A= =fevT -----END PGP SIGNATURE----- --=-9l8I9BRvSR2PD70rtTqf--