From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: XFS corruption during power-blackout Date: Fri, 1 Jul 2005 20:41:45 +0200 Message-ID: <20050701184145.GA3055@suse.de> References: <42C54BDC.6000206@emc.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ric Wheeler , linux-fsdevel@vger.kernel.org, =?iso-8859-1?Q?Rog=E9rio?= Brito , Brett Russ Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:24789 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S263428AbVGASkn (ORCPT ); Fri, 1 Jul 2005 14:40:43 -0400 To: Bryan Henderson Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Fri, Jul 01 2005, Bryan Henderson wrote: > >>But how does the end-user know what hardware is "good hardware"? Which > >>vendors don't lie (or, at least, lie less than others) regarding HDs? > >> > > > >The only real way is to test the drive (and retest when you get a new > >versions of firmware) and the whole fsync -> write barrier code path. > > Wouldn't a commercial class drive that ignores explicit flushes be > infamous? I'm ready to accept that there are SCSI drives that cache > writes in volatile storage by default (but frankly, I'm still skeptical), > but I'm not ready to accept that there are drives out there secretly > ignoring explicit commands to harden data, thus jeopardizing millions of > dollars' worth of data. I'd need more evidence. I'm pretty sure I have an IBM drive that does so (its flush cache command is _really_ fast), as a matter of fact :-) I need to locate it and put it in a test box to re-ensure this. I'm not sure such drives would necessarily be infamous, hardly anyone would notice anything wrong in a desktop type machine. Which is what these drives were made for. -- Jens Axboe