From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 8 13:57:42 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 305D91065675 for ; Mon, 8 Nov 2010 13:57:42 +0000 (UTC) (envelope-from cronfy@gmail.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id AF98C8FC29 for ; Mon, 8 Nov 2010 13:57:40 +0000 (UTC) Received: by bwz3 with SMTP id 3so4891041bwz.13 for ; Mon, 08 Nov 2010 05:57:40 -0800 (PST) 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:content-type; bh=txe4DO7Is+idhxuOEpqrGZa5UwKiglQr99k4z3Pdc6M=; b=WetQEfFWYGf4jHYMHWBsXSiT7nnGKIKxVYn/ClYesvfXGFcUwrBCCyz6EBf3Z9zzQj 59pBpk2S6BwYVK9CvtanSIhfetBHqkUXXZeC+frk7zmLoTHr5L5KrbQFR26fcL3gchz9 2QguTKXd4+eKkwVAZiJ9wAacc1FSx09QFLf4M= 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 :content-type; b=xVyxdSA87cNOo4C3yPlFZRhg5a9YfVuTkhJcGfiNbx07XB1gkyek4J6Tt//X/xN57H cc3EhRrmFJYUcHpLNfaJBmQQznXXsJhpbFSU7cCsbxTGIF8kVz9mmrvGkpKAdXOl22Wn 5GaIdcNouwvU2wBPVGY5VVH77LxIiM+TOAgws= Received: by 10.204.73.75 with SMTP id p11mr4953710bkj.46.1289224660308; Mon, 08 Nov 2010 05:57:40 -0800 (PST) MIME-Version: 1.0 Received: by 10.204.73.135 with HTTP; Mon, 8 Nov 2010 05:57:09 -0800 (PST) In-Reply-To: <201010302237.o9UMb157032371@apollo.backplane.com> References: <201010302237.o9UMb157032371@apollo.backplane.com> From: cronfy Date: Mon, 8 Nov 2010 16:57:09 +0300 Message-ID: To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: Slow disk access while rsync - what should I tune? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Nov 2010 13:57:42 -0000 Hello. Thanks again. > Yes, hardlinked backups pretty much destroy performance, mainly > because it destroys all locality of reference on the storage media > when files are slowly modified and get their own copies, mixed with > other 'old' files which have not been modified. But theoretically > that should only effect the backup target storage and not the server's > production storage. That is what surprised me when I did experiment with backups. If I move backup off from the production server (to another less loaded production server indeed), server that shuld be backed up starts to run fine while backups are created. I think it means that problem is not with vnode/dir caches.. At the other side the server who received backups became very slow. So the problem looks to be related to writes or file creation/hardlinking somehow... At the moment I do not have server with ZFS, but I will think in this direction. But I heard that ZFS has less performance than UFS, is it really like this? I mean I have seen benchmarks and system requirements, but would like to hear about your own experience. -- // cronfy