From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeny Koryanov Subject: Raid recovery. Help wanted! Date: Sun, 21 Apr 2013 20:16:54 +0400 Message-ID: <517410F6.8050605@maris.no> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids 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 state after power jump. Server supplied by UPS but this seems was not good enough - server was 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: picture repeated rebuild fails. So I have sdb in sync state, sdc - failed and sdd spare. I checked SMARTs of drives to understand reason of such behavior and found it clean on all devices. Than I tried to dd if=/dev/sd[bcd] of=/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 should be possible to try recover data (meaning that bads appears in quite different places)... May be you know utility which helps recover data or the way how to start array in read-only mode preventing becomes it to degraded state and force md device to try recover data using readable places from each devise??? Or any other ideas appreciated! Thanks, any way... Best regards, Evgeny.