From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: Write cache on SATA drives? Date: Fri, 1 Jul 2005 10:54:13 +0200 Message-ID: <20050701085412.GA2243@suse.de> References: <20050701062416.GQ2243@suse.de> <20050701083308.GZ2243@suse.de> <20050701084717.GA18306@merlin.emma.line.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:35470 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S263278AbVGAIwm (ORCPT ); Fri, 1 Jul 2005 04:52:42 -0400 Content-Disposition: inline In-Reply-To: <20050701084717.GA18306@merlin.emma.line.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Edwards, Scott (GE Healthcare)" , linux-scsi@vger.kernel.org On Fri, Jul 01 2005, Matthias Andree wrote: > Jens Axboe schrieb am 2005-07-01: > > > On Fri, Jul 01 2005, Matthias Andree wrote: > > > Jens Axboe writes: > > > > > > > On Thu, Jun 30 2005, Edwards, Scott (GE Healthcare) wrote: > > > >> Hello, > > > >> > > > >> Can anyone tell me if the write cache on SATA drives are handled such > > > >> that journaling file systems work correctly? Back in the 2.6.5 - > > > >> 2.6.7 time frame I had to disable the write cache to get ext3 to not > > > >> trash things when the power was lost. With kernel 2.6.10 would I > > > >> still need to disable the write cache? > > > > > > > > With 2.6.12.x it should work, if you use ext3 or reiser and the > > > > appropriate mount options (-o barrier=1 for ext3, barrier=flush for > > > > reiserfs). 2.6.11 and earlier does not work on SATA. > > > > > > I presume this means "libata" exclusively, no? > > > > It means "SCSI without queueing" which I'm assuming is basically only > > libata at this moment, at least if you count setups that have a non-zero > > userbase :) > > > > > Which is the oldest version where this works > > > > > > 1. for SCSI (perhaps by adaptor)? > > > > 2.6.12, with the above restriction. I hope to lift that for .13/14, with > > Tejuns barrier updates. > > The "SCSI without queueing" isn't clear to me. What system exactly is > meant "without queueing"? > > Does this mean SCSI with TCQ is safe? > > Does this means SCSI is safe only when TCQ isn't used? > > Does this apply to internals of the SCSI host adaptor driver? > > I'm not acquainted with kernel/block I/O queueing internals. SCSI without TCQ or with TCQ depth=1 should be safe, provided the driver never reorders a command once it has received it. > > > 2. for traditional IDE (such as VIA 82*, PIIX_*)? > > > > In SUSE kernels, for many years. Since 2.6.7/8'ish in Linus' kernels. > > I don't care for vendor kernels. Is listing 2.6.8 safe? Check the changelogs, I can't remember exactly if it was 2.6.7 or 2.6.8 (or perhaps .6...). -- Jens Axboe