From mboxrd@z Thu Jan 1 00:00:00 1970 From: raz ben jehuda Subject: Re: when does it become faulty disk Date: Mon, 20 Jun 2005 13:09:44 +0300 Message-ID: <1119262184.3076.1.camel@raz-laptop> References: <5d96567b05061804477325d743@mail.gmail.com> <62b0912f05061912103ad3c459@mail.gmail.com> <1119249803.3094.8.camel@raz-laptop> <62b0912f05062000557bd05348@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <62b0912f05062000557bd05348@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Molle Bestefich Cc: linux-raid List-Id: linux-raid.ids thank you molle. This was a very helpful information. On Mon, 2005-06-20 at 10:55, Molle Bestefich wrote: > raz ben jehuda wrote: > > So, what about write errors ? > > from what you are saying i understand that when a write error occurs > > the disk is faulty. > > Yes.. If you are serious about your data redundancy, yes. > > A sector _read_ error is a notification from the disk that a sector > has gone bad and that some particular data is lost. > > A sector _write_ error is the disk telling you that: > 1. The sector has gone bad. > 2. The disk failed to relocate the sector to the spare area, probably > because it's full. > > The above are slight simplifications, since other kinds of read and > write errors may in very rare cases occur. That's OK though, since > you DO want sick disks with strange internal errors that are causing > read or write errors to get kicked. > > In rare cases a disk could get sick in a way where writes to a bad > sector succeeds but subsequent reads fail. Never seen it happen... > But just in case, you might want to re-read a failed sector after you > have written to it, just to check that the disk actually correctly > relocated it. > > Once a disk has been kicked, you may want to instruct the user to > check that the disk's spare sector count has indeed reached 0, by > using smartctl -a /dev/xxx. That command will also tell of other disk > failures. -- Raz Long Live The Penguin