From owner-svn-src-stable-8@FreeBSD.ORG Thu Dec 10 23:51:24 2009 Return-Path: Delivered-To: svn-src-stable-8@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 76BBC1065670; Thu, 10 Dec 2009 23:51:24 +0000 (UTC) (envelope-from mav@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 4B69F8FC08; Thu, 10 Dec 2009 23:51:24 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id nBANpO8V078610; Thu, 10 Dec 2009 23:51:24 GMT (envelope-from mav@svn.freebsd.org) Received: (from mav@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id nBANpOKc078607; Thu, 10 Dec 2009 23:51:24 GMT (envelope-from mav@svn.freebsd.org) Message-Id: <200912102351.nBANpOKc078607@svn.freebsd.org> From: Alexander Motin Date: Thu, 10 Dec 2009 23:51:24 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org X-SVN-Group: stable-8 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r200373 - stable/8/sbin/geom/class/mirror X-BeenThere: svn-src-stable-8@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for only the 8-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Dec 2009 23:51:24 -0000 Author: mav Date: Thu Dec 10 23:51:24 2009 New Revision: 200373 URL: http://svn.freebsd.org/changeset/base/200373 Log: MFC r200282, r200290: Change gmirror default balance algorithm from "split" to improved "load". "split" is very ineffective for devices with rotating media as HDDs. To be effective, it needs that transfer time reduction due to block splitting was bigger then access time increase due to non-sequential access. For modern HDDs I was able to reproduce it only with read sizes of 2MB and above, which is almost not applicable in real life. "load" algorithm same time is more universal and effective now. Modified: stable/8/sbin/geom/class/mirror/geom_mirror.c stable/8/sbin/geom/class/mirror/gmirror.8 Directory Properties: stable/8/sbin/geom/ (props changed) Modified: stable/8/sbin/geom/class/mirror/geom_mirror.c ============================================================================== --- stable/8/sbin/geom/class/mirror/geom_mirror.c Thu Dec 10 23:46:37 2009 (r200372) +++ stable/8/sbin/geom/class/mirror/geom_mirror.c Thu Dec 10 23:51:24 2009 (r200373) @@ -44,7 +44,7 @@ __FBSDID("$FreeBSD$"); uint32_t lib_version = G_LIB_VERSION; uint32_t version = G_MIRROR_VERSION; -static char label_balance[] = "split", configure_balance[] = "none"; +static char label_balance[] = "load", configure_balance[] = "none"; static intmax_t label_slice = 4096, configure_slice = -1; static intmax_t insert_priority = 0, configure_priority = -1; Modified: stable/8/sbin/geom/class/mirror/gmirror.8 ============================================================================== --- stable/8/sbin/geom/class/mirror/gmirror.8 Thu Dec 10 23:46:37 2009 (r200372) +++ stable/8/sbin/geom/class/mirror/gmirror.8 Thu Dec 10 23:51:24 2009 (r200373) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd August 1, 2009 +.Dd December 8, 2009 .Dt GMIRROR 8 .Os .Sh NAME @@ -135,6 +135,7 @@ Specifies balance algorithm to use, one .Bl -tag -width ".Cm round-robin" .It Cm load Read from the component with the lowest load. +This is the default balance algorithm. .It Cm prefer Read from the component with the biggest priority. .It Cm round-robin @@ -142,7 +143,6 @@ Use round-robin algorithm when choosing .It Cm split Split read requests, which are bigger than or equal to slice size on N pieces, where N is the number of active components. -This is the default balance algorithm. .El .It Fl F Do not synchronize after a power failure or system crash.