From owner-freebsd-fs@FreeBSD.ORG Mon Sep 6 11:10:16 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 B2A9510656C6 for ; Mon, 6 Sep 2010 11:10:16 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 057008FC1C for ; Mon, 6 Sep 2010 11:10:15 +0000 (UTC) Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua [212.40.38.101]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id OAA00703; Mon, 06 Sep 2010 14:10:13 +0300 (EEST) (envelope-from avg@icyb.net.ua) Message-ID: <4C84CC15.5000907@icyb.net.ua> Date: Mon, 06 Sep 2010 14:10:13 +0300 From: Andriy Gapon User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.2.8) Gecko/20100823 Lightning/1.0b2 Thunderbird/3.1.2 MIME-Version: 1.0 To: Kostik Belousov References: <7EA7AD058C0143B2BF2471CC121C1687@multiplay.co.uk> <1F64110BFBD5468B8B26879A9D8C94EF@multiplay.co.uk> <4C83A214.1080204@DataIX.net> <06B9D23F202D4DB88D69B7C4507986B7@multiplay.co.uk> <4C842905.2080602@DataIX.net> <330B5DB2215F43899ABAEC2CF71C2EE0@multiplay.co.uk> <4C84C857.1070306@icyb.net.ua> <20100906110406.GC2396@deviant.kiev.zoral.com.ua> In-Reply-To: <20100906110406.GC2396@deviant.kiev.zoral.com.ua> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=KOI8-U Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: zfs very poor performance compared to ufs due to lack of cache? 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: Mon, 06 Sep 2010 11:10:16 -0000 on 06/09/2010 14:04 Kostik Belousov said the following: > On Mon, Sep 06, 2010 at 01:54:15PM +0300, Andriy Gapon wrote: >> on 06/09/2010 02:57 Steven Hartland said the following: >>> Based on Jeremy's comments I'm updating the box the stable. Its building now >>> but will be the morning before I can reboot to activate changes as I need to >>> deactivate the stream instance and wait for all active connections to finish. >>> >>> That said the problem doesn't seem to be cache + free but more cache + free >>> + inactive with inactive being the large chunk, so not sure this change >>> would make any difference? >>> >>> How does ufs deal with this, does it take inactive into account? Seems a bit >>> silly for inactive pages to prevent reuse for extended periods when the >>> memory could be better used as cache. >> >> Inactive pages are also a cache, just a different kind. > Not quite. Inactive pages may be dirty. Such pages cannot be freed or reused > without pageout. Yes, they can be dirty, but I didn't say that inactive was a "clean-only" cache. ARC entries can also be dirty and it's still a cache. -- Andriy Gapon