From owner-freebsd-questions@FreeBSD.ORG Fri Apr 24 19:56:06 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9286F106572F for ; Fri, 24 Apr 2009 19:56:06 +0000 (UTC) (envelope-from freebsd-questions@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id 1B6CE8FC12 for ; Fri, 24 Apr 2009 19:56:05 +0000 (UTC) (envelope-from freebsd-questions@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LxRVC-0005BL-B3 for freebsd-questions@freebsd.org; Fri, 24 Apr 2009 19:56:02 +0000 Received: from 78-1-171-208.adsl.net.t-com.hr ([78.1.171.208]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 24 Apr 2009 19:56:02 +0000 Received: from ivoras by 78-1-171-208.adsl.net.t-com.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 24 Apr 2009 19:56:02 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-questions@freebsd.org From: Ivan Voras Date: Fri, 24 Apr 2009 21:55:31 +0200 Lines: 56 Message-ID: References: <32442523.2901240597865043.JavaMail.HALO$@halo> <22026228.2921240597983327.JavaMail.HALO$@halo> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7924CD881E36D00D279C6349" X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 78-1-171-208.adsl.net.t-com.hr User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) In-Reply-To: <22026228.2921240597983327.JavaMail.HALO$@halo> X-Enigmail-Version: 0.95.7 Sender: news Subject: Re: Unexpected gmirror behavior: Is this a bug? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Apr 2009 19:56:06 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7924CD881E36D00D279C6349 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Peter Steele wrote: > We had a somewhat startling scenario occur with gmirror. We have system= s with four drives ad4, ad6, ad8, and ad10, with the OS setup on a mirror= ed slice across all four drives. The ad4 drive failed at one point, due t= o a simple bad connection in its drive bay. While it was offline, the sys= tem was continued to be used for a while and new data was added to the mi= rrored file system.=20 >=20 > We eventually took the box down to deal with ad4, and tried simply pull= ing and reinserting the drive. On reboot we saw that the BIOS detected th= e drive, so that was good. However, when FreeBSD got to the point of star= ting up the GEOM driver, instead of reinserting ad4 into the more current= mirror consisting of ad6/ad8/ad10 and resyncing it with that data, the G= EOM driver assumed ad4 was the "good" mirror and ended up resyncing ad6/a= d8/ad10 with the data from ad4, causing the new files we had added to tho= se drives to be lost.=20 >=20 > This only happens with ad4. If ad6 for example goes offline in the same= way, when it is reinserted it does not become the dominant drive and res= ync its data with the other drives. Rather its data is overwritten with t= he data from the 3 member mirror, as you'd expect.=20 >=20 > So, clearly ad4, the first disk, is treated specially. The question is = this a bug or a feature? Is there anyway to prevent this behavior? This w= ould be a disastrous thing to happen in the field on one of our customer = systems.=20 This definitely looks like a bug. Try asking again on the freebsd-geom@ list. Provide output of "gmirror list". =46rom what you said it looks like you did the procedure safely - you turned off the server, then pulled the drive and reinserted it, then turned it on again, right? --------------enig7924CD881E36D00D279C6349 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 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAknyGTMACgkQldnAQVacBcjjJACgwbx8jJBiYP6VJbYB1aAJcnaA DzsAniHCD2ViR981VNow8eUaEDKf6tJ4 =zO7H -----END PGP SIGNATURE----- --------------enig7924CD881E36D00D279C6349--