From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263823AbTDUL6k (ORCPT ); Mon, 21 Apr 2003 07:58:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263824AbTDUL6k (ORCPT ); Mon, 21 Apr 2003 07:58:40 -0400 Received: from 81-2-122-30.bradfords.org.uk ([81.2.122.30]:33152 "EHLO 81-2-122-30.bradfords.org.uk") by vger.kernel.org with ESMTP id S263823AbTDUL6i (ORCPT ); Mon, 21 Apr 2003 07:58:38 -0400 From: John Bradford Message-Id: <200304211213.h3LCDJlq000623@81-2-122-30.bradfords.org.uk> Subject: Re: Are linux-fs's drive-fault-tolerant by concept? To: vda@port.imtp.ilyichevsk.odessa.ua Date: Mon, 21 Apr 2003 13:13:19 +0100 (BST) Cc: john@grabjohn.com (John Bradford), skraw@ithnet.com (Stephan von Krawczynski), linux-kernel@vger.kernel.org In-Reply-To: <200304211113.h3LBDuu08057@Port.imtp.ilyichevsk.odessa.ua> from "Denis Vlasenko" at Apr 21, 2003 02:22:01 PM X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > Name an IDE or SCSI disk on sale today that doesn't retry on write > > failiure. Forget I said 'Generally do'. > > I don't know about drives currently on sale, but I think > it is possible that some Flash or DRAM-based IDE pseudo-disks > do not have extensive sector remapping features. They can just > do ECC thing and error out. Flash devices generally have wear-leveling, so I assume that they must be doing some extensive sector remapping all the time. I could be wrong on that account, though. > Also if disk just runs out of spare sectors, it has no other > option other than just report failure, right? (Oh, > of course it can decide to execute 'my firmware is buggy' > option instead ;) Yeah, but if a device which is intellegent about bad-block remapping actually runs out of spare sectors, that's a different failiure that having a single defective sector. In a server, it would definitely be time to replace it. > But. > > The disk, which I hold in my hand *right now*, namely: > WD Caviar 21200 > MDL: WDAC21200-00H > P/N: 99-004211-000 > CCC: E3 2 APR 97 S > DCM: AFAAYAW > WD S/N: WT342 251 1943 > > does have some bad sectors and otherwise performs satisfactorily. OK. > It's my 'big diskette'. [snip] Then why don't we invent a new filesystem, for known potentially faulty media, which handles this case - why bloat all the existing filesystems with code to handle it? That idea isn't that far away from the extra layer I suggested a few posts ago, and achieves the same sort of thing. John.