From owner-cvs-all@FreeBSD.ORG Fri Sep 17 17:20:41 2004 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2DE2916A4CE; Fri, 17 Sep 2004 17:20:41 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id C757843D45; Fri, 17 Sep 2004 17:20:40 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.254.11] (junior-wifi.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.12.11/8.12.10) with ESMTP id i8HHK3vQ013089; Fri, 17 Sep 2004 11:20:03 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <414B1C94.606@samsco.org> Date: Fri, 17 Sep 2004 11:19:16 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20040831 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Brooks Davis References: <98480.1095438391@critter.freebsd.dk> <414B10FB.9030003@samsco.org> <20040917170302.GT30151@darkness.comp.waw.pl> <20040917171503.GB10367@odin.ac.hmc.edu> In-Reply-To: <20040917171503.GB10367@odin.ac.hmc.edu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: src-committers@FreeBSD.org cc: Pawel Jakub Dawidek cc: cvs-src@FreeBSD.org cc: cvs-all@FreeBSD.org cc: Poul-Henning Kamp cc: Robert Watson cc: Giorgos Keramidas cc: Ceri Davies Subject: Re: cvs commit: src/sys/sys mdioctl.h src/sys/dev/md md.csrc/sbin/mdconfig Makefile mdconfig.8 mdconfig.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Sep 2004 17:20:41 -0000 Brooks Davis wrote: > On Fri, Sep 17, 2004 at 07:03:02PM +0200, Pawel Jakub Dawidek wrote: > >>On Fri, Sep 17, 2004 at 10:29:47AM -0600, Scott Long wrote: >>+> >Uhm, be aware that we are limited also to the size of individual >>+> >swap disks. 31 bits of bytes/sectors/pages, not quite sure which. >>+> > >>+> >>+> 32 bits of pages, unless there is somewhere in the chain that the >>+> unsigned nature of the word is not being honored. >> >>Pages. It gives as maximum swap-backed device of 16TB. I tested it with >>~15TB devices, so there is no signed/unsigned problem (which will limit >>us to 8TB). Of course you can always (I hope) increase page size:) > > > Given my quick read of the sunlabel format, there would be some value in > >>16TB (17 would be sufficent) virtual disks. Can we do a RAID0 of these > > to get something that big? I'm pretty sure sunlabel is limited to 14TB > or 16TB so having something too big would be good for testing. > > -- Brooks > The 16TB limit comes not from md or from the block layer or disk layer or whatnot, it comes from using 4k pages for swap backing and only being about to address these pages using 32 bit numbers. The important part of the I/O path have already been converted (or are in the process of being converted) to use 64 bit numbers. Scott