From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 30 May 2014 14:40:20 +0100 From: "Richard W.M. Jones" Message-ID: <20140530134020.GK1302@redhat.com> References: <20140522180405.GA6361@redhat.com> <20140522181334.GE1302@redhat.com> <20140529135246.GA31293@redhat.com> <20140529203410.GG1954@redhat.com> <20140529204719.GD1302@redhat.com> <20140529210648.GA3955@redhat.com> <20140529211955.GE1302@redhat.com> <20140529215815.GA4183@redhat.com> <20140530090422.GB31293@redhat.com> <20140530133814.GB8830@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140530133814.GB8830@redhat.com> Subject: Re: [linux-lvm] Testing the new LVM cache feature Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mike Snitzer Cc: Heinz Mauelshagen , Zdenek Kabelac , thornber@redhat.com, LVM general discussion and development On Fri, May 30, 2014 at 09:38:14AM -0400, Mike Snitzer wrote: > Why are you setting {read,write}_promote_adjustment to 1? I asked you > to set write_promote_adjustment to 0. I didn't realize there would be (much) difference. However I will certainly try it with write_promote_adjustment == 0. > Your random fio job won't hit the same blocks, and md5sum likely uses > buffered IO so unless you set 0 for both the cache won't aggressively > cache like you're expecting. Right, that was definitely a mistake! I will drop_caches between each md5sum operation. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/