From owner-svn-src-head@FreeBSD.ORG Wed Jan 6 17:38:34 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3761A1065670; Wed, 6 Jan 2010 17:38:34 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from mail-ew0-f226.google.com (mail-ew0-f226.google.com [209.85.219.226]) by mx1.freebsd.org (Postfix) with ESMTP id 48B168FC20; Wed, 6 Jan 2010 17:38:33 +0000 (UTC) Received: by ewy26 with SMTP id 26so15688705ewy.3 for ; Wed, 06 Jan 2010 09:38:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:from:date:x-google-sender-auth:message-id:subject:to:cc :content-type:content-transfer-encoding; bh=23GwsrLpZyhJDHsw/d12ISCZG4f5e8Vrc5ic1Eo+MZU=; b=bI8u4ZHyy6FCWCxgLt6tjmG66qvJN9pIm18IGkXoFDglQ9P0i6TCUmch473MOZ8wkE yFlfSnOGu1nWiAFsGI4DOxHFhJ8g3u8kYiM2wtO2p+CQygOyxR5f/7Xy6bchMBs/h/An 2TdDcyBAYUH9IKa6X1g8AvVkoNs3lUfXEQozM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=ZkJQssAdhMo+NYuKWVuB6sMnaVA7W3hXzyY3I4TaToSno0IerKQOVhdZbss3Lce9PR /fQbjKSXqbiRaG2PAjhxMfs9jJhUcPF/xH2XFQqYAb23OSzAxdRaJ0dsXs20eARBQpuK 5e9GICSVLv8U95cTeol4SzWOFR+w/D1F1IV4M= MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.216.90.210 with SMTP id e60mr1511911wef.120.1262799508120; Wed, 06 Jan 2010 09:38:28 -0800 (PST) In-Reply-To: <201001061712.o06HCICF087127@svn.freebsd.org> References: <201001061712.o06HCICF087127@svn.freebsd.org> From: Ivan Voras Date: Wed, 6 Jan 2010 18:38:07 +0100 X-Google-Sender-Auth: f59e6cd615f45e48 Message-ID: <9bbcef731001060938k2b0014a2m15eef911b9922b2c@mail.gmail.com> To: Alexander Motin Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r201658 - head/sbin/geom/class/stripe X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Jan 2010 17:38:34 -0000 2010/1/6 Alexander Motin : > Author: mav > Date: Wed Jan =C2=A06 17:12:18 2010 > New Revision: 201658 > URL: http://svn.freebsd.org/changeset/base/201658 > > Log: > =C2=A0Increase default block size from 4K to 64K. It was reduces 6 yeard = ago, > =C2=A0when trees were big and FAST mode was enabled by default. > > =C2=A0So small block size doesn't benefits linear I/O operations in FAST = and > =C2=A0significantly slowdowns in ECONOMIC (default) mode. For single stre= am random > =C2=A0I/Os so small block doesn't give much benefits, as access time is u= sually > =C2=A0bigger then transfer time there. Same time it requires all heads to= seek > =C2=A0together for every single request, reducing performance on parallel= load. I think there was one more reason - though I'm not sure if it is still valid because of your current and future work - the MAXPHYS limitation. If MAXPHYS is 128k, with 64k stripes data was only to be read from maximum of 2 drives. With 4k stripes it would have been read from 128/4=3D32 drives, though I agree 4k is too low in any case nowadays. I usually choose 16k or 32k for my setups.