From owner-freebsd-stable@FreeBSD.ORG Tue Aug 2 10:37:52 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9A8B3106564A for ; Tue, 2 Aug 2011 10:37:52 +0000 (UTC) (envelope-from daniel@digsys.bg) Received: from smtp-sofia.digsys.bg (smtp-sofia.digsys.bg [193.68.3.230]) by mx1.freebsd.org (Postfix) with ESMTP id 1EA328FC15 for ; Tue, 2 Aug 2011 10:37:51 +0000 (UTC) Received: from dcave.digsys.bg (dcave.digsys.bg [192.92.129.5]) (authenticated bits=0) by smtp-sofia.digsys.bg (8.14.4/8.14.4) with ESMTP id p72AARU0006708 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Tue, 2 Aug 2011 13:10:33 +0300 (EEST) (envelope-from daniel@digsys.bg) Message-ID: <4E37CD13.1070402@digsys.bg> Date: Tue, 02 Aug 2011 13:10:27 +0300 From: Daniel Kalchev User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:5.0) Gecko/20110720 Thunderbird/5.0 MIME-Version: 1.0 To: freebsd-stable@freebsd.org References: <20110802090830.GA92646@icarus.home.lan> <20110802094226.GA93114@icarus.home.lan> <42039B84-D6CE-4780-AA70-8500B1B32036@gsoft.com.au> In-Reply-To: <42039B84-D6CE-4780-AA70-8500B1B32036@gsoft.com.au> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: ZFS directory with a large number of files X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Aug 2011 10:37:52 -0000 On 02.08.11 12:46, Daniel O'Connor wrote: > I am pretty sure UFS does not have this problem. i.e. once you > delete/move the files out of the directory its performance would be > good again. UFS would be the classic example of poor performance if you do this. > If it is a limitation in ZFS it would be nice to know that, perhaps it > truly, really is a bug that can be avoided (or it's inherent in the > way ZFS handles such things) It is possible that there is not enough memory in ARC to cache that large directory. Other than that, perhaps in ZFS it would be easier to prune the unused directory entries, than it is in UFS. It looks like this is not implemented. Another reason might be some FreeBSD specific implementation issue for fstatfs. In any case, the data available is not sufficient. More information would help, like how much RAM this system has, how much ARC uses, some ARC stats. What made me wonder is .. how exactly the kernel and zpool disagree on zpool version? What is the pool version in fact? Daniel