From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Bug#658701: mdadm: should send email if mismatches are reported by a check Date: Mon, 28 May 2012 11:41:30 +1000 Message-ID: <20120528114130.31b6c1db@notabene.brown> References: <20120205123450.21371.88843.reportbug@xev> <4F2E90AD.3020405@msgid.tls.msk.ru> <4F872CED.7050809@msgid.tls.msk.ru> <4FC0EB0C.1080800@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/X8rPIF4kHihl3x8=3LHPRF7"; protocol="application/pgp-signature" Return-path: In-Reply-To: <4FC0EB0C.1080800@msgid.tls.msk.ru> Sender: linux-raid-owner@vger.kernel.org To: Michael Tokarev Cc: 658701@bugs.debian.org, linux-raid List-Id: linux-raid.ids --Sig_/X8rPIF4kHihl3x8=3LHPRF7 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 26 May 2012 18:39:08 +0400 Michael Tokarev wrote: > Neil, can you comment on the change to Monitor offered > in the mentioned bugreport please? >=20 > On 12.04.2012 23:28, Michael Tokarev wrote: > > Neil, re http://bugs.debian.org/658701 , how do you think, > > is it okay if mdadm --monitor will send email in case check > > found mismatches, the same way it sends email about other > > more critical errors? > >=20 > > I think Russell has a good point here, but there's one more > > source of mismatches we have in kernel - some "sporadic" > > mismatches in raid1 and raid10, especially when these are > > used as swap space... > >=20 > > In Debian we've several bugreports already requesting more > > attention to mismatch_cnt, see: > >=20 > > http://bugs.debian.org/658701 (this one) > > http://bugs.debian.org/599821 > > http://bugs.debian.org/588516 > >=20 > > Thank you! > >=20 > > /mjt Sorry for not replying the first time :-( I do not agree with the suggested change to mdadm. A non-zero mismatch count may not be a problem. It could be due to swap writing to a RAID1/RAID10. It could also be due to a RAID1/RAID10/RAID6 having been created with --assume-clean. This is perfectly safe thing to do but results in a non-zero mismatch_cnt. mdadm --monitor will run a program on every event. If someone wants more events reported than currently are reported, they are free to write a script to do whatever they like. If md finds unreadable blocks and fixes them, then that certainly might be interesting. However that is interesting much more broadly than just for md, and I believe 'smart' makes that information available. So having it reported from SMART would be more sensible. In brief: mismatch_cnt maybe useful to someone who understands what is means and is investigating some issues, but it is not something that should be automatically reported to a casual sysadmin. NeilBrown --Sig_/X8rPIF4kHihl3x8=3LHPRF7 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT8LXyjnsnt1WYoG5AQIk/g/9FudU93wRxPgam/UUg4VTSMWjttUADDXs 4eEasVmcBemsvL7UIohGcFeiWQUC2HC3i+rteP1Eh46zUP9+Fvec830gg/wxRRxR znwpNsoO0ZqmLP4OTNLPPVEPTONQsOXCMtETfXOVz8WZIYF4Xtj5g6wHyBt4CKWl B93Ch9WtknhvA6oyDwCxdTWzUXrkzgJnIKDv4jgQZdliQzcdRR9Fv889N7QjIzzz MUiYQhU4qwIPlZeDuAiz+Mt06je4GSja/IHhJqD4J2mJjJsPEmqR7qsnbUM21Pum YEznTvZaYU7WGTdmavvOj3WLvYwMTWbY8bmQecvYeSUpwPbWN/lP21oGTG7MDY+5 5AZ3p8kbtz0R/WqU5VHNKNCo1AbJUrTSqmHoACcHw/vZOzK1Xg7QJ5By3/a4AgPF xktNSSe6vyfFxzr6I+Ey/5Hc5RGUMLlOTp6Cdf99ewDjX1sXSGFc7NNhZFXMKn3K vIChFIS1VeomrnXLIuiLkZ2n33HS6z7UjbovHgd3NmyKQ4Zl+AIFL/GE0hpjwram wQ1h0Cqqi5WroxHoHvoAzn74psTG9hVWPUm68wwF8JlNF8JqnVNm1qXJwtbEOBKR cnvf+WF1+gPfKATY1f/PkonO+QMFrhjMlDxzOtyX6Yc2AVajs+uzBvZOw2uotmlu gP9KzKHOOGA= =noKb -----END PGP SIGNATURE----- --Sig_/X8rPIF4kHihl3x8=3LHPRF7--