From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Bad block management - which mdadm? Date: Tue, 25 Oct 2011 09:46:16 +1100 Message-ID: <20111025094616.78384241@notabene.brown> References: <201110242212.14934.a.miskiewicz@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/vK4xy.i/I7_Puwc+UDTv2Op"; protocol="application/pgp-signature" Return-path: In-Reply-To: <201110242212.14934.a.miskiewicz@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Arkadiusz =?utf-8?B?TWnFm2tpZXdpY3o=?= Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/vK4xy.i/I7_Puwc+UDTv2Op Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Mon, 24 Oct 2011 22:12:14 +0200 Arkadiusz Mi=C5=9Bkiewicz wrote: >=20 > kernelnewbies.org reports such feature for 3.1 kernel >=20 > 1.9. Software RAID: Bad block management > The MD layer (aka "Multiple Devices", aka software raid) has gained bad b= lock=20 > management support: bad blocks will be added to a list, and the system wi= ll=20 > try not to use them. This feature requires an updated mdadm version. >=20 > Which mdadm supports that? >=20 mdadm-3.3 will support bad block management. However it is not released yet. You can get current code from git://neil.brown.name/mdadm devel-3.3 It isn't released yet because 1/ I haven't found/made time to work on mdadm and integrate support properly. 2/ The kernel isn't really quite read for full support. If you have a bad block list, then a write error will not fail the drive but will record the location of the write error. This might be what you want. But if you have a hot-spare available it might not be what you want - the current kernel code will never use a hot spare until a drive fails really badly. What it *should* do is "hot-replace". i.e. recover the data on to a spare without first removing the device with the bad block. But the hot-replace code isn't ready yet. I expect hot-replace to be in linux-3.3 (for RAID4/5/6 at least) and I hope= to release mdadm-3.3 before then with full support for bad blocks and hot replace. For now if you use the devel-3.3 code to create a new array it will place a bad-block-log on the array and the kernel will use that bad block log to record failed blocks rather than failing the whole device. If you want a device to be failed, you might have to explicitly do that yourself with "mdadm /dev/mdX --fail /dev/sdY" NeilBrown --Sig_/vK4xy.i/I7_Puwc+UDTv2Op Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTqXqvTnsnt1WYoG5AQLbjg//av4lHbnZL0MvuG6Ay+TuZb0EoX3jFm41 AcYLneCVo0Hk9TEkzGZ55QC9JIxszkSVy8V6JNnywb3NYXRLVi30t3Zmqr54kWJ2 cy0ketwg0lRcufJpzwbxp6WfSDF7qo2ZQ5aOELxOlGXOSrIJomnzyszlVJzyLVf5 u28Gv9xMa2G/aubMLsljUw+8dNVjACfX4jPORlS4U+nnKVYYuwV3s0zUiCWx+jAZ ah8ayvTTwZ2iYjG1gv2qF1Vf4L1syjvTYx1DvhNwwR9EMMFXg6g5IQCsqlZZs9j8 jHkk2hJ955ehN7IpiwknIjH/Fa+KyM5VxVYSg4LfLCgB2+3kOqxbMYULuZCdsoph I8O55XWO+6CU7UWolJ90WGglO2othc6GLlh3w29Yjq6hGI6zfAmZWaxOEHc2b25n 32ScHvXjWO8LDLhzooYT0ff5AC+3UjL7RC2MGTSo2REXWduwboLD8SepL99fUeZB YmX+pE6uO3i8o4F7ROoUhTpda2hm7yvI2wTZf4dIowFUcmnAtuseJl0v/oZiIRoy d2uP/hE4Qd5JXbwJpqhfO5WXn5nCcq4cgib0Qj+P1xrgzXimt2UCgeZhzoayDkRa 7fjYvCGNBRpHCOG3IsNGh0f7rPBWELJtGuPugyStGxnZk3K7PrwHgG2gN+/o2bZs T/pZbe2labg= =Vi1i -----END PGP SIGNATURE----- --Sig_/vK4xy.i/I7_Puwc+UDTv2Op--