From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [PATCH 0/6] raid6check fixes Date: Thu, 27 Jun 2013 14:27:19 +1000 Message-ID: <20130627142719.5ffbf0ce@notabene.brown> References: <20130618090910.1161109.69430.stgit@fsdevel7.hpc.devnet.itwm.fhg.de> <20130619100803.03fde6d5@notabene.brown> <20130620161639.GA3033@lazy.lzy> <20130624170458.568dafcb@notabene.brown> <20130624171016.GA2237@lazy.lzy> <20130625095422.29d3079b@notabene.brown> <20130625164628.GA2261@lazy.lzy> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/nt7gQNsN/A7kJPD6_lLfjcg"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20130625164628.GA2261@lazy.lzy> Sender: linux-raid-owner@vger.kernel.org To: Piergiorgio Sartor Cc: Bernd Schubert , linux-raid@vger.kernel.org, Robert Buchholz List-Id: linux-raid.ids --Sig_/nt7gQNsN/A7kJPD6_lLfjcg Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 25 Jun 2013 18:46:28 +0200 Piergiorgio Sartor wrote: > On Tue, Jun 25, 2013 at 09:54:22AM +1000, NeilBrown wrote: > [...] > > I don't remember holding back on any raid6check patches, but then I ten= d to > > forget such things - usually after I've replied with why, but sometimes > > before. > >=20 > > If there are patches that you (or anyone else) think should be in but a= ren't, > > please point them out to me. I'll either apply them or explain why I d= on't > > want to. >=20 > Hi Neil, >=20 > no, you did not seem to have forgot anything. > I quickly checked mdadm-3.3-rc1 source and it > seems raid6check.c is up to date. >=20 > > > > Do you mean when will it be included by distros? That is really up= to them. > > > > I could get "make install" to install it I guess. > > > > I haven't really thought about what would be required for that. > > > >=20 > > > > I'll add it to my list of things to think about. > > >=20 > > > Well, that could be some thinking for 3.3, couldn't it? :-) > >=20 > > It could indeed. >=20 > Well, do not forget... :-) >=20 I've just had a little look at raid6test - because some of the selftests we= re failing. The default output is rather verbose. Verbose output can be good, but not = as the default I think. However, more importantly, it pays too much heed to the chunksize. If the start of one chunk on drive X is bad, and the end of a corresponding chunk on drive Y is bad, then it will complain that it cannot figure out the problem. It shouldn't do that. It shouldn't even look at whole chunks at a time. It should look at blocks. Maybe 512bytes or 1K or 4K any of those would do. Then for each block it should figure out if there is a problem, and maybe auto-fix it. Having two blocks on different drives being bad might be cause for extra warnings, but it doesn't make any difference if they are in the same stripe or in different stripes. i.e. the chunksize should be used only as part of the calculation to work o= ut the layout at any particular place in the array. It should not be used as a unit for reading and writing data. In anyone feels like addressing that issue, I would be very receptive to patches :-) NeilBrown --Sig_/nt7gQNsN/A7kJPD6_lLfjcg Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIVAwUBUcu/Jznsnt1WYoG5AQK/oBAAlHE+t0D4xeceEBkmhQjydCp2J6y0UJKU XbUUSIFeMuQOZ/ZpvMK73FY707PE4fjNTfgnkkJ3aTKIBarn6riQDEAj2IYPR6sD Usr74QBXeh9gxvDJ1WvBRtwiX+pnk776IAX+ergQAIjlhvCYrgXLT+gXRSbWrABN s/a+YybY8ATjnBuz4UCqtW/13luxseAzo0K7LmNBbqMDp96k3yhx5wl5IV+DNUrY FEA6I5nmwFJ0wnHPTIdP8Cj9jKYp5/mP2cpKIirVQjPM5KmyrmfjN4nR+ainNMMg 1iouKqDPYBUay5WolnRWMwGDcqbaFGw++MYrT5UrE8vi3EEdG+NBwdaxNhxV70ef 9Zknagx4TLe4dVbxK19ERHIo5Dfm2Vsf3JHlwnSJt62p6BcNCtv6XUiXBTmAsW9w NleGO8+ohZlThwDnDvMOBtn0eHADyzn95LWsAQBDI6eDTgb+FPKGNx5EKumc4eSs AhceC0PJZtLuxVbzBAn+/uQH4oOlt8TvB4yOfOy05SytIDQdxQ91gQd4opO0IGKs TGmSuBXfV0Zy+FzjsrqeM1ehA9PoVvSzbjLnmi1M51GMseevjBjohgTOhX6RWUP+ dpF4lJ02MzNPszYd5r0E0O9n1vMp/Ps+km4EldP/UqRCyrz+NIhyI4uQmb73gWHb FVKHnGOQGro= =EcII -----END PGP SIGNATURE----- --Sig_/nt7gQNsN/A7kJPD6_lLfjcg--