From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [PATCH 0/2] Modify read error handle for RAID-4,5,6. Date: Thu, 28 Jun 2012 10:04:04 +1000 Message-ID: <20120628100404.7fa60770@notabene.brown> References: <201205261052422815923@gmail.com> <20120627143228.21ee4baa@notabene.brown> <201206271403526562112@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/qIpg2xWLDEbpEZzH9jMSdza"; protocol="application/pgp-signature" Return-path: In-Reply-To: <201206271403526562112@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: majianpeng Cc: linux-raid List-Id: linux-raid.ids --Sig_/qIpg2xWLDEbpEZzH9jMSdza Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 27 Jun 2012 14:03:55 +0800 majianpeng wrote: > On 2012-06-27 12:32 NeilBrown Wrote: > >On Sat, 26 May 2012 10:52:50 +0800 "majianpeng" w= rote: > > > >> When RAID-4,5,6 degraded and met read-error, it will eject the rdev.An= d then > >> the RAID will fail and lost data.Because the function of set-badsector= ,when=20 > >> this occur,it will set-badsector,not ejecting the rdev. > >> When RAID-4,5,6 met read-error, it will re-write if RAID was not degra= de.But if=20 > >> re-write error,it will eject the rdev and RAID will degrade and it wil= l take too > >> long time for recoverying.So I add judgement for controling how may re= -write-error > >> can eject the rdev. > >>=20 > >> I do those for flexible controling the read-error for different situat= ion. > >> =09 > > > >Thanks. > > > >>=20 > >> majianpeng (2): > >> md/raid456: When readed error and raid was degraded,it try to > >> set badsector, not ejecting the rdev. > > > >I've applied this one. I also added 'set_bad =3D 1' in the case where > >the re-write failed. > > > >> md/raid456:Add interface for contorling eject rdev when re-write > >> failed. > > > >I haven't applied this. I'm not entirely sure what the point of counting > >the errors was, but I don't think it is necessary. > Using raid456,the first object is to protect data.But in some situation, = the user > can endure lost some data instead of raid degraed or failed. > After introduce the badblocks, I think md-driver should do flexible contr= oling for > error.The controling can control by different user for different requirme= nt. I cannot see the point of that control though. Sure you *always* want to record a bad block if possible, if the alternative is ejecting the whole device? I don't see where the choice would be between "lost data" or "degraded arra= y". Maybe if the failing device caused large delays then you want to eject it soon rather than struggling on with it. However my belief is that if you don't want long delays, then you should tell the device to fail rather than impose long delays. It is not something that md should care about. So: still a little confused. NeilBrown --Sig_/qIpg2xWLDEbpEZzH9jMSdza Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT+ufdDnsnt1WYoG5AQLBtw//ZXvGBjOhXwEKyHQxY6fKYimvvPP/Nmau HvRLKP7Dk6q1zwxCBl7p4ib5dKdn6gNdnLeaV7amJcEes5yVCIP+e0L55DXckRis xe3e3GNPDhUXC4ljveKdhkt9dLgfUuq+EQJi4gixDRgDHV7U+7m8ov2d05Z3WcpV bY1dzKRbDTPH3mY6jaaGh/gX3gC2JT9ao1reea9quQFK3v5BbOOmIB+ZK4yRKoTb DKln5byuLGGdIXDOWYQaP0i01CarlvETJaKW/biFuSwGR0x2KNT4VOVlyvySWEUs jqM7KANv1gdVVLdInqx8KNIpVIUsnsSUhSdG5uyMhPoW6Ws4apKMK1eak3BrOFs8 AfWXzmpLCBtFwE8r9kjbftlKVy2mUSLPp+wePzs17qzEx5PnOgq1+ju60Cod37IN RJiT9JOf+d6gcvdo0FbxhP64hTrax1sneMbXLt8FlrBomgZbuhxQMAIiA2zxuS+M BYi6fTlIhDjjrlyXoj+omdMkg2vWZUekPMKwsVZL2It+YloxEPkSLUoFy+YuYOba xh28jtr87A+Av7jVdjUmd/0HHIVHDzTrRTSnp8kPKYHL6mC8TEIPEpU4f4rtqFqb lj18GLp+l87ZJVzeFM0p/8gVJwuG6XJXoCUFufsQ0Y0LceWKYZIHsokYpSD5x/KL KoP2+fR0TEI= =2r92 -----END PGP SIGNATURE----- --Sig_/qIpg2xWLDEbpEZzH9jMSdza--