From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeny Koryanov Subject: Re: Raid recovery. Help wanted! Date: Sun, 21 Apr 2013 21:27:30 +0400 Message-ID: <51742182.5040702@maris.no> References: <517410F6.8050605@maris.no> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: =?UTF-8?B?TWF0aGlhcyBCdXLDqW4=?= Cc: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids On 21.04.2013 20:40, Mathias Bur=C3=A9n wrote: > On 21 April 2013 17:16, Evgeny Koryanov wr= ote: >> Hello everybody! >> >> Yesterday I met a problem with one of raid5 arrays build by mdadm on= three >> (sd[bcd]) 1.5T devices. >> I found array in degraded state with sdd fail. Drive becomes fail st= ate >> after power jump. >> Server supplied by UPS but this seems was not good enough - server w= as not >> rebooted but one drive as I said becomes fail state. >> I simply reattaches it and array started rebuilding but fails after = couple >> of %'s passed with sdc becomes fail!!! >> I assemble array again with sd[bc] and tried to attach sdd again: pi= cture >> repeated rebuild fails. >> So I have sdb in sync state, sdc - failed and sdd spare. I checked S= MARTs of >> drives to understand reason of such behavior and >> found it clean on all devices. Than I tried to dd if=3D/dev/sd[bcd] >> of=3D/dev/null and found that dd also fails with IO error. >> After dd bad blocks started appears in SMART :) >> Finally I have: >> sdb - sync >> sdc - fail >> sdd - spare >> states and a number of bads on each hdd in random places... >> >> Could any one suggest how can I assemble this array now in read-only= mode to >> try to copy data?! >> Theoretically data on sdd should not be rewritten and it still shoul= d be >> possible to try recover data (meaning that bads appears in quite dif= ferent >> places)... >> May be you know utility which helps recover data or the way how to s= tart >> array in read-only mode preventing becomes it to degraded state >> and force md device to try recover data using readable places from e= ach >> devise??? >> Or any other ideas appreciated! Thanks, any way... >> >> Best regards, >> Evgeny. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid= " in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > Hi, > > Could you post the smartctl -a output of all the drives? If 2 drives > are failling you might want to derescue them somewhere and assemble > the RAID from that. > > Mathias Hi, Mathis. Will post it tomorrow - it's down now and I'm not around. But as per your suggestion: still not clear for me is it good idea - as= =20 soon as I will copy valid data to another drive information about bad's places will be lost (for md device driver) and=20 bad blocks physically will be replaced by zeros. And what will happen after assembling and trying to read places where=20 bad blocks was (where array marked sync and blocks are not consistent - redundant part zeroed) - will md read properly? will m= d=20 mark drive fail as soon as find async (zeroed) block ans start resync..= =2E=20 Actually I did not found in mdadm read-only assembling mode which will=20 prevent such behavior! Best regards, Evgeny. * English - detected * English * Russian * Norwegian * English * Russian * Norwegian -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html