From owner-freebsd-fs@FreeBSD.ORG Wed May 19 08:47:19 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1AA0E1065673 for ; Wed, 19 May 2010 08:47:19 +0000 (UTC) (envelope-from mgamsjager@gmail.com) Received: from fg-out-1718.google.com (fg-out-1718.google.com [72.14.220.159]) by mx1.freebsd.org (Postfix) with ESMTP id 9D1B18FC21 for ; Wed, 19 May 2010 08:47:18 +0000 (UTC) Received: by fg-out-1718.google.com with SMTP id 22so1901085fge.13 for ; Wed, 19 May 2010 01:47:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:received:in-reply-to :references:from:date:message-id:subject:to:cc:content-type; bh=TxkIiKajGrP4fbXg620qct58VgIHviIKqhWUCoe1z+M=; b=irlh09cCJCZ3qQ1AVisV4IhzzvhmK77vYw7AnpE0ZAoduZ5fMNeuVROWUQy8dWxQhG 7L3luNbHFqpdRU5qEWpZdq3dRsg+xgcx2xBiAi1M0IoM6b+C2D8qM83HPEo76VZrljwV 1Br5L3HD+rk/2+6u2cBaO9DsyqLM0SylAEpDg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=ETCLT94vDtP0VWdMYqUIqDnPrWq/4wj+3AKsBboPjbSERCnpf/oAgLDdO6dp+gqkr5 37V5lavIoWyCWxxI0zdoDX+Qeazdchxyv7m526z/lxpl3pf9Y9l4kLTnZobC+iZoRLiD R655TLTxGRUywlohW4pTlKifax5Et8OloxnWI= Received: by 10.103.78.10 with SMTP id f10mr5847896mul.126.1274258836956; Wed, 19 May 2010 01:47:16 -0700 (PDT) MIME-Version: 1.0 Received: by 10.204.78.194 with HTTP; Wed, 19 May 2010 01:46:46 -0700 (PDT) In-Reply-To: <4BF3A0DD.4080404@tzim.net> References: <4BF3A0DD.4080404@tzim.net> From: Matthias Gamsjager Date: Wed, 19 May 2010 10:46:46 +0200 Message-ID: To: Arnaud Houdelette Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-fs@freebsd.org Subject: Re: ZFS Recordsize tuning & transmission (bittorent daemon) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 May 2010 08:47:19 -0000 > > ZFS recordsize on both pools are default (128k). But as transmission > bittorrent client has no write (nor read) cache, it could mean that data is > written is smaller chunks during download. Could this lead to data being > stored in many not-full records ? Does those unfull records would have to be > read as whole (128k) during the move, which would explain the above > difference on read/write ? > > I'm just making assumptions here, as my understanding of internals of ZFS is > limited. Some insights would be appreciated. > Well ZFS does not write immediately but waits couple of seconds and write them in 1 single write operation. could you give more info about what freebsd version do you use, hardware used, zfs parameters in /boot/loader.conf and zfs info like compression etc... did you test your pool with Iozone to see if it performance as it should?