From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f180.google.com ([209.85.223.180]:35678 "EHLO mail-io0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756112AbcAZAoi (ORCPT ); Mon, 25 Jan 2016 19:44:38 -0500 Received: by mail-io0-f180.google.com with SMTP id 77so170011927ioc.2 for ; Mon, 25 Jan 2016 16:44:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <56A230C3.3080100@netcologne.de> <56A6082C.3030007@netcologne.de> Date: Mon, 25 Jan 2016 18:44:37 -0600 Message-ID: Subject: Fwd: btrfs-progs 4.4 re-balance of RAID6 is very slow / limited to one cpu core? From: Justin Brown To: linux-btrfs Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: > Does anyone suspect a kernel regression here? I wonder if its worth it > to suggest testing the current version of all fairly recent kernels: > 4.5.rc1, 4.4, 4.3.4, 4.2.8, 4.1.16? I don't have any useful information about parity RAID modes or large arrays, so this might be totally useless. Nonetheless, just last week I added a 2TB drive to an existing Btrfs raid10 array (5x 2TB before addition) and did a balance afterwards. I don't take any numbers, but I was frequently looking at htop and iotop. I thought the numbers were extremely good: 100-120MB/s sustained for each drive with the "total" reported by iotop exceeding 600MB/s. That's with integrated sata controller on an Intel Z97 mini-ITX motherboard (cpu i4770). Significantly faster than anticipated. I started it one evening, and it was finished when I awoke the next morning. That was on 4.2.8-300.fc23.x86_64 with btrfs-progs 4.3.1.