From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:34745 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751165AbbKZQ2Q (ORCPT ); Thu, 26 Nov 2015 11:28:16 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1a1zP0-0008P4-HN for linux-btrfs@vger.kernel.org; Thu, 26 Nov 2015 17:28:10 +0100 Received: from ip98-167-165-199.ph.ph.cox.net ([98.167.165.199]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 26 Nov 2015 17:28:10 +0100 Received: from 1i5t5.duncan by ip98-167-165-199.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 26 Nov 2015 17:28:10 +0100 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: Using Btrfs on single drives Date: Thu, 26 Nov 2015 16:27:44 +0000 (UTC) Message-ID: References: <201511251820.25758.russell@coker.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Russell Coker posted on Wed, 25 Nov 2015 18:20:25 +1100 as excerpted: > On Sun, 15 Nov 2015 03:01:57 PM Duncan wrote: >> That looks to me like native drive limitations. >> >> Due to the fact that a modern hard drive spins at the same speed no >> matter where the read/write head is located, when it's reading/writing >> to the first part of the drive -- the outside -- much more linear drive >> distance will pass under the read/write heads in say a tenth of a >> second than will be the case as the last part of the drive is filled -- >> the inside -- and throughput will be much higher at the first of the >> drive. > > http://www.coker.com.au/bonnie++/zcav/results.html > > The above page has the results of my ZCAV benchmark (part of the > Bonnie++ suite) which shows this. You can safely tun ZCAV in read mode > on a device that's got a filesystem on it so it's not too late to test > these things. Thanks. Those graphs are pretty clear. As you, I'd have thought there'd be far fewer zones (3-4) than it turns out there are (8ish). -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman