From owner-freebsd-fs@freebsd.org Tue Apr 26 12:44:42 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 45CAEB1C6FF for ; Tue, 26 Apr 2016 12:44:42 +0000 (UTC) (envelope-from 000.fbsd@quip.cz) Received: from elsa.codelab.cz (elsa.codelab.cz [94.124.105.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0AC451C67 for ; Tue, 26 Apr 2016 12:44:41 +0000 (UTC) (envelope-from 000.fbsd@quip.cz) Received: from elsa.codelab.cz (localhost [127.0.0.1]) by elsa.codelab.cz (Postfix) with ESMTP id 6B64F28426 for ; Tue, 26 Apr 2016 14:44:33 +0200 (CEST) Received: from illbsd.quip.test (ip-86-49-16-209.net.upcbroadband.cz [86.49.16.209]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by elsa.codelab.cz (Postfix) with ESMTPSA id 58EB028428 for ; Tue, 26 Apr 2016 14:44:29 +0200 (CEST) Message-ID: <571F62AD.6080005@quip.cz> Date: Tue, 26 Apr 2016 14:44:29 +0200 From: Miroslav Lachman <000.fbsd@quip.cz> User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:35.0) Gecko/20100101 Firefox/35.0 SeaMonkey/2.32 MIME-Version: 1.0 To: freebsd-fs@freebsd.org Subject: How to speed up slow zpool scrub? Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 26 Apr 2016 12:44:42 -0000 Hi, is there any way to make zpool scrub faster? We have one older machine with CPU Pentium(R) Dual E2160 @1.80GHz, 5GB of RAM and 4x 4TB HDDs. It is just a storage for backups for about 20 machines. Scrub is scheduled from periodic each 30 days but it takes about 4 days to complete and everything during scrub is slow. Backups takes 8 hours instead of 5 (made by rsync), deleting of old files is even more slower. The backups are made every night from the midnight to morning, the machine is idle for the rest of the day. Is there any tuning to make scrub faster in this idle time? Or is it better to do it other way - slower scrub with even lower priority taking for about one week but not affecting time of normal operations? (is it dangerous to have scrub running this long or reboot machine during the scrub?) I have a performance graphs of this machine and CPU is about 70% idle during scrub, but hard drives are busy 75% (according to iostat) FreeBSD 10.3-RELEASE amd64 GENERIC Miroslav Lachman