From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc MERLIN Subject: Re: brtfs on top of dmcrypt with SSD. No corruption iff write cache off? Date: Wed, 1 Feb 2012 19:23:45 -0800 Message-ID: <20120202032345.GB31903@merlins.org> References: <20120130003754.GD4380@merlins.org> <20120201175624.GE16796@shiny> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Chris Mason , linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <20120201175624.GE16796@shiny> List-ID: On Wed, Feb 01, 2012 at 12:56:24PM -0500, Chris Mason wrote: > > Second, I was wondering if anyone is running btrfs over dmcrypt on an SSD > > and what the performance is like with write cache turned off (I'm actually > > not too sure what the impact is for SSDs considering that writing to flash > > can actually be slower than writing to a hard drive). > > Performance without the cache on is going to vary wildly from one SSD to > another. Some really need it to give them nice fat writes while others > do better on smaller writes. It's best to just test yours and see. > > With a 3.2 kernel (it really must be 3.2 or higher), both btrfs and dm > are doing the right thing for barriers. Thanks for the answer. Can you confirm that I still must disable write cache on the SSD to avoid corruption with btrfs on top of dmcrypt, or is there a chance that it just works now? Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/