From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:38675 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752566Ab3F1OAA (ORCPT ); Fri, 28 Jun 2013 10:00:00 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1UsZDS-0007oT-UP for linux-btrfs@vger.kernel.org; Fri, 28 Jun 2013 15:59:58 +0200 Received: from cpc21-stap10-2-0-cust974.12-2.cable.virginmedia.com ([86.0.163.207]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 28 Jun 2013 15:59:58 +0200 Received: from m_btrfs by cpc21-stap10-2-0-cust974.12-2.cable.virginmedia.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 28 Jun 2013 15:59:58 +0200 To: linux-btrfs@vger.kernel.org From: Martin Subject: raid1 inefficient unbalanced filesystem reads Date: Fri, 28 Jun 2013 14:59:45 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On kernel 3.8.13: Using two equal performance SATAII HDDs, formatted for btrfs raid1 for both data and metadata and: The second disk appears to suffer about x8 the read activity of the first disk. This causes the second disk to quickly get maxed out whilst the first disk remains almost idle. Total writes to the two disks is equal. This is noticeable for example when running "emerge --sync" or running compiles on Gentoo. Is this a known feature/problem or worth looking/checking further? Regards, Martin