From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Port Multiplier access with Sil 3124 Date: Mon, 09 Feb 2009 19:15:10 -0500 Message-ID: <4990C70E.1010707@garzik.org> References: <498F42B6.8030607@tlinx.org> <87f94c370902090635h2fc3e604n990bdd70be9c48cd@mail.gmail.com> <4990AC91.8010104@tlinx.org> <87f94c370902091501h96ecb8dp7acac1fa80a82d8a@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:52105 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751990AbZBJAPP (ORCPT ); Mon, 9 Feb 2009 19:15:15 -0500 In-Reply-To: <87f94c370902091501h96ecb8dp7acac1fa80a82d8a@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Greg Freemyer Cc: Linda Walsh , linux-ide@vger.kernel.org Greg Freemyer wrote: > I'm hearing of people saying a 2 disk mirror (raid-1) is not safe > enough. Go with either a 3 disk mirror or to raid-6. Even with > raid-6 I personally would not let it have too many spindles. (Whatever > too many means?) IMO, RAID-1 was never safe. With RAID-1, one must rely solely on "knowing" which RAID component is bad. With a completely dead drive, this is obvious; with slowly creeping bad sectors, far less obvious. Plus, the biggest crime, in my opinion, is the lack of checksumming or any other method of actually verifying your data. I've been waiting for years for someone to write RAID-1f... RAID-1 with a hash function that writes checksums in a special metadata area (just like the other pre-existing RAID metadata... a RAID partition is really a just simple filesystem anyway). That way you _know_ with 100% certainty that your data is OK (or not), even if you only have a single drive. Jeff