From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: Questions about 4k sector drives Date: Mon, 03 May 2010 16:19:47 -0400 Message-ID: References: <4BD42B57.9000703@kusche.de> <1272206601.7734.4.camel@faldara> <4BDE0512.8070502@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: (Greg Freemyer's message of "Mon, 3 May 2010 09:30:01 -0400") Sender: linux-raid-owner@vger.kernel.org To: Greg Freemyer Cc: Bill Davidsen , Phillip Susi , Florian Kusche , linux-raid@vger.kernel.org, "Martin K. Petersen" List-Id: linux-raid.ids >>>>> "Greg" == Greg Freemyer writes: Greg> In theory 4K physical sector drives with XP alignment will Greg> eventually ship and possibly have already. Well, that's a definite maybe :) The 4K transition took much longer than anticipated and Vista and beyond know how to query the drives for alignment. So I'm guessing that we'll only see 1-alignment via a jumper at this point. Greg> I don't know it any those drives exist yet, or if they ever will. I have a bunch, but obviously they are mostly prototypes. Greg> mdadm should as well, not just blindly say 1MB is the magic Greg> alignment point. (ie. linux can do better than Win2008/Win2003 Greg> which simply disagree with each other on how to align.) We're going with 1MB as default because that's the new storage industry consensus. It's a less formalized number than - say - IDEMA sector counts, but it appears to have reached critical mass among the vendors. And obviously we'll compensate if the storage device reports a different alignment via the relevant ATA or SCSI knobs. -- Martin K. Petersen Oracle Linux Engineering