From owner-freebsd-fs@FreeBSD.ORG Tue Aug 8 16:07:33 2006 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0716916A4E0 for ; Tue, 8 Aug 2006 16:07:33 +0000 (UTC) (envelope-from anderson@centtech.com) Received: from mh1.centtech.com (moat3.centtech.com [207.200.51.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8057443D46 for ; Tue, 8 Aug 2006 16:07:32 +0000 (GMT) (envelope-from anderson@centtech.com) Received: from [10.177.171.220] (neutrino.centtech.com [10.177.171.220]) by mh1.centtech.com (8.13.1/8.13.1) with ESMTP id k78G7VxX039472; Tue, 8 Aug 2006 11:07:31 -0500 (CDT) (envelope-from anderson@centtech.com) Message-ID: <44D8B6D6.6070209@centtech.com> Date: Tue, 08 Aug 2006 11:07:50 -0500 From: Eric Anderson User-Agent: Thunderbird 1.5.0.5 (X11/20060802) MIME-Version: 1.0 To: Q References: <06530464-7491-4BC1-97C7-87285B03F2EB@gmail.com> In-Reply-To: <06530464-7491-4BC1-97C7-87285B03F2EB@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.87.1/1640/Mon Aug 7 20:11:04 2006 on mh1.centtech.com X-Virus-Status: Clean Cc: freebsd-fs@freebsd.org Subject: Re: Problem with ufs not releasing vm_pages on busy volume. (soft updates related) 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: Tue, 08 Aug 2006 16:07:33 -0000 On 08/08/06 00:14, Q wrote: > On 02/08/2006, at 8:10 PM, Q wrote: > >> I have a problem that seems to be related to something ufs related >> not releasing some vm_pages on busy filesystems. I have two servers >> running PostgreSQL, one running 6.0-RELEASE, the other 6.1-RELEASE. >> Both are under the same (fairly heavy) load, performing the same >> operations in bursts every five minutes. The filesystems in >> question are 450-500Gig, each server using a different brand of >> RAID card, they both have soft-updates enabled. >> >> The problem is that both servers are seeing an accumulation of >> about 100Mb of active pages per day (looking at >> vm.stats.vm.v_active_count) that never get released. The only way >> to release these pages is to unmount the filesystem and remount it. >> Failing to do this results in the server eventually locking up. >> >> If someone could provide me with some direction on how to go about >> tracking down what might be causing this to happen it would be much >> appreciated. > > I have narrowed the cause of this issue down further to something to > do with soft updates. If I turn off soft updates for the filesystem > hosting the database the system no longer accumulates active vm_pages > constantly. Instead for accumulating 100Mb a day of active vm pages > until all memory is consumed, it will hover around 50-60Mb with soft > updates disabled. > > If someone familiar with the softupdates code is willing to help me > pinpoint the cause of this problem it would be much appreciated. > Is it possible for you to upgrade to the latest 6-STABLE branch, just to make sure that the issue hasn't been fixed already? Is there any way to reproduce this on another box for testing? (I assume not, due to the nature of these things) Also - I wonder if doing a snapshot on the filesystem would flush out the pages - is that something you can try? Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------