From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: mdadm and disk failures Date: Thu, 16 Jun 2011 10:59:08 +0600 Message-ID: <20110616105908.474d22bc@natsu> References: <4DF97A7B.1070901@dodtsair.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/17GAR60NTo/eAtBwc8_uqqA"; protocol="application/pgp-signature" Return-path: In-Reply-To: <4DF97A7B.1070901@dodtsair.com> Sender: linux-raid-owner@vger.kernel.org To: Mike Power Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/17GAR60NTo/eAtBwc8_uqqA Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 15 Jun 2011 20:37:31 -0700 Mike Power wrote: > From what I understand when a hard drive loses a block it replaces it=20 > with another block but it can not recover the data. > If it read from the disk that had the block it gets garbage for data. This is not true, an HDD will never return garbage data just because it nee= ded to remap a bad sector. And that's the reason why bad sectors will return I/O error (unreadable) instead, and are not remapped anywhere until you try to WRITE into these sectors. At that moment, when the hard disk has new user d= ata for that sector, it can finally do the remap and put it somewhere else on a remapped good sector. --=20 With respect, Roman --Sig_/17GAR60NTo/eAtBwc8_uqqA Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk35jZwACgkQTLKSvz+PZwghnACgjF8sSbdRQWXbYLF+TwrvNKV6 N74AoI6W7M0HflSHwu0X6dRhmzdAeAfH =7ROB -----END PGP SIGNATURE----- --Sig_/17GAR60NTo/eAtBwc8_uqqA--