From owner-freebsd-stable@FreeBSD.ORG Wed Aug 10 10:44:05 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 9416B106566B for ; Wed, 10 Aug 2011 10:44:05 +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 1B6398FC16 for ; Wed, 10 Aug 2011 10:44:04 +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 p7AAgBII050421 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Wed, 10 Aug 2011 13:42:17 +0300 (EEST) (envelope-from daniel@digsys.bg) Message-ID: <4E426083.1020207@digsys.bg> Date: Wed, 10 Aug 2011 13:42:11 +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: Jeremy Chadwick References: <4E4143A6.6030307@digsys.bg> <20110809151646.GF1814@albert.catwhisker.org> <4E422F8A.1070508@digsys.bg> <20110810074759.GA30254@icarus.home.lan> <4E423CAC.20008@digsys.bg> <20110810084759.GA32346@icarus.home.lan> In-Reply-To: <20110810084759.GA32346@icarus.home.lan> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: FreeBSD-STABLE Mailing List Subject: Re: 32GB limit per swap device? 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: Wed, 10 Aug 2011 10:44:05 -0000 On 10.08.11 11:47, Jeremy Chadwick wrote: > So we're back to where we started: swap slices/partitions can be > greater than 32GBytes in size, but "something" is limiting the maximum > amount of memory which can be dumped to a single swap swap to 32GBytes. It seems there is still some confusion. Partition size(s) is 64GB, but FreeBSD will use only 32GB of that for swap. Trying: sysctl debug.minidump=0 sysctl debug.kdb.panic=1 Produces 64GB dump, but.. I can't see the dump on the swap device (savecore doesn't find the magic number). My swap device is gmirror or two slices (/dev/mirror/swap). Removing the gmirror and listing both slices for swap .. works. I could use separate device for dumps, but the disk real estate on this particular blade is limited... Well, I really asked two questions: Q1: Is FreeBSD still limited to 32GB per swap slice? A1: yes. There is limit set in /usr/src/sys/vm/swap_pager.c Q2: If FreeBSD will only use 32GB of the slice for swap, will it dump larger (64GB in my case) core in there? A2a: yes. A2b: If the swap slice is gmirrored, you don't get any dump back. I believe the gmirror bug might exist in smaller partitions as well, but haven't tested it yet (have few such systems that never duped core). It does not matter if I do full dump or minidump: on gmirrored 64GB partittion savecore does not find anything. Daniel