From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Subject: Re: raid0 fail to detect drive failure Date: Wed, 02 Nov 2005 08:40:47 -0500 Message-ID: <1130938847.9447.111.camel@localhost.localdomain> References: <1130860974.9447.19.camel@localhost.localdomain> <4368822A.4050400@tls.msk.ru> Reply-To: mingz@ele.uri.edu Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4368822A.4050400@tls.msk.ru> Sender: linux-raid-owner@vger.kernel.org To: Michael Tokarev Cc: Linux RAID List-Id: linux-raid.ids On Wed, 2005-11-02 at 12:08 +0300, Michael Tokarev wrote: > Ming Zhang wrote: > > Hi folks > > > > I have a raid0 on top of 2 sata disk sda and sdb. after i hot unplug > > sda, the raid0 still shows online and active. run dd to write to it will > > fail and dmesg shows scsi io error. but /proc/mdstat shows everything is > > ok. > > Since raid0 isn't relly raid (as Redundrand) and can't really do > anything with IO errors on component devices, this behaviour > (returning IO errors to the application) is the only sane way > to go. It should not fail just like when your disk drive has > a bad sector on it, the whole partition (or whole disk) with > that bad sector isn't "marked as failed". So what you see is > exactly correct behaviour, in my opinion anyway. > > /mjt after I sent email, I read the raid0 code and there is no error handling at all, so i knew why it looks like that. for my case, 2 disk raid0, 1 disk broke mean 50% sectors on a disk are bad. i would like to call that disk a failed disk. and i bet you will not use such disk any more even you call it not-failed disk. ;) but as you said, raid0 is not a real raid, so maybe this is why no error check here. thanks! Ming