From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: Feature Request Date: Tue, 09 Feb 2010 15:28:10 +0300 Message-ID: <4B7154DA.90405@msgid.tls.msk.ru> References: <4B712034.1000600@gmx.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B712034.1000600@gmx.net> Sender: linux-raid-owner@vger.kernel.org To: st0ff@npl.de Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Stefan *St0fF* Huebner wrote: [] > Now imagine any RAID with some kind of redundancy, reading/writing > data. One of the disks finds out "I cannot correctly read/write the > requested sector", starts its error correction, hits the respective > ERC-timeout and reports back a media error or unrecoverable error. Now > mdraid would drop the disk. > > But actually the data of the sector can be recreated through the > existing redundancy. Wouldn't it be a smart thing if the mdraid > recreates the sector and just tried to write it again? And after a good > amount of failed retries it may well drop the disk. This is exactly what md layer is doing. On failed _read_ it tries to reconstruct data from other disk drives and writes the reconstructed data back to the drive where read failed. If the _write_ fails md will drop the disk. /mjt