From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: Removing a failing drive from multiple arrays Date: Thu, 26 Apr 2012 07:19:14 +0100 Message-ID: <4F98E8E2.6070503@anonymous.org.uk> References: <4F905F66.6070803@tmr.com> <20369.29756.761374.308057@quad.stoffel.home> <4F918F5C.2000607@anonymous.org.uk> <4F9450D1.40305@anonymous.org.uk> <4F98B4FE.5010101@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F98B4FE.5010101@tmr.com> Sender: linux-raid-owner@vger.kernel.org To: Bill Davidsen Cc: Linux RAID List-Id: linux-raid.ids On 26/04/2012 03:37, Bill Davidsen wrote: > John Robinson wrote: [...] >> Without either hardware or BIOS RAID, you can still end up being >> unable to boot, >> e.g. the BIOS will try to boot from the first hard drive present, but >> if it has >> bad sectors in the MBR or /boot partition, booting may fail even >> though there's >> a perfectly good mirror on the second drive, because the BIOS doesn't >> understand >> RAID. This has happened to me :-( >> > Doesn't need to understand RAID, just be willing to try the next item in > the boot list on failure. My experience has been that almost every BIOS > will try the 2nd item if the 1st fails totally (ie. drive isn't there). > A _good_ BIOS will try the next item on sector error in the MBR. Absolutely - but in the case I had, grub couldn't load its next stage because of a sector error. It probably didn't help that the weekly array scrubs don't touch the space between the MBR and the first partition, where that code lives. > After that the BIOS needs to understand a lot more to do anything > smart after the MBR runs. Agreed; only a RAID BIOS (software e.g. IMSM or hardware RAID card) could have saved me from the above failure. Cheers, John.