From owner-freebsd-stable@FreeBSD.ORG Tue Jun 27 01:32:06 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DB55E16A401 for ; Tue, 27 Jun 2006 01:32:06 +0000 (UTC) (envelope-from noackjr@alumni.rice.edu) Received: from mail.clickfox.com (cffw1.clickfox.com [72.16.213.34]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3EC4943D48 for ; Tue, 27 Jun 2006 01:32:05 +0000 (GMT) (envelope-from noackjr@alumni.rice.edu) X-PMWin-Version: 2.5.1s, Antispam-Engine: 2.3.0.1, Antivirus-Engine: 2.34.3 thread-index: AcaZijmFabYnmvxhS+u6p1p447+YUA== X-PMWin-Spam: Gauge=IIIIIIII, Probability=8%, Report='__HAS_MSGID, __SANE_MSGID, __USER_AGENT, __MIME_VERSION, __CT, __CTYPE_CHARSET_QUOTED, __CT_TEXT_PLAIN, __CTE, __MIME_TEXT_ONLY' Received: from [10.20.30.156] ([72.16.213.34]) by mail.clickfox.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.1830); Mon, 26 Jun 2006 21:37:17 -0400 Message-ID: <44A08A94.9060700@alumni.rice.edu> Date: Mon, 26 Jun 2006 21:32:04 -0400 From: "Jonathan Noack" User-Agent: Thunderbird 1.5.0.4 (Windows/20060516) MIME-Version: 1.0 To: "Marc G. Fournier" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.2663 Content-Class: urn:content-classes:message Importance: normal Priority: normal References: <20060624221556.O30039@woozle.rinet.ru> <20060626143038.GK79678@deviant.kiev.zoral.com.ua> <20060626152345.M1114@ganymede.hub.org> <200606262244.25505.max@love2party.net> <20060626185437.I1114@ganymede.hub.org> In-Reply-To: <20060626185437.I1114@ganymede.hub.org> Content-Type: text/plain; format=flowed; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 27 Jun 2006 01:37:17.0515 (UTC) FILETIME=[397519B0:01C6998A] Cc: Kostik Belousov , Max Laier , freebsd-stable@freebsd.org, Dmitry Morozovsky Subject: Re: vmstat 'b' (disk busy?) field keeps climbing ... X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: noackjr@alumni.rice.edu List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Jun 2006 01:32:06 -0000 Marc G. Fournier wrote: > On Mon, 26 Jun 2006, Max Laier wrote: >> On Monday 26 June 2006 20:25, Marc G. Fournier wrote: >>> I think I might have found *at least* one of the problems, and that >>> being >>> the excessively high blocked states while ps isn't finding anything ... >>> >>> MySQL >>> >>> We just recently started allowing clients to run a MySQL server *within* >>> their vServer ... in a drastic move, I just shut them all down on pluto, >>> and blocked drop'd from ~86 down to 5 in a matter of moments ... >>> restarting them all has it climbing once more, being up around 22 >>> already >>> ... >>> >>> I'm going to go with that theory for now, and keep an eye on things ... >>> >>> Just curious as to why, even with -H, its not showing any blocked states >>> within ps though ... ? >> >> The "blocked" column shows also processes that have objects "paging". >> Most likely you are *short* on memory. In order to relieve the >> pressure program .text pages are free'ed and need to be refetched from >> disc whenever the respective code is being executed. > > 'k, but shouldn't the OS be doing any swapping, if this was the case? > I'm getting <1M of swappage when the blocked pages are really high ... It makes sense when you think about it (as Matthew Fuller pointed out in this thread 2 days ago). There is no point in swapping out binary pages as they are ALREADY stored on disk and can be re-fetched with ease (remember the binary is marked in use so we don't have to worry about it getting modified out from under us); why double disk usage by storing binaries on the swap partition? In this case, binary pages are getting paged out under memory pressure and have to be paged back in when needed. This results in high vnode pager activity but little swap pager activity. Matthew pointed out that the vnode pager also handles mmap()'d files, which could come into play with MySQL. -Jonathan