From owner-freebsd-hackers@FreeBSD.ORG Thu Sep 16 18:19:14 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E5BBF16A4CE for ; Thu, 16 Sep 2004 18:19:14 +0000 (GMT) Received: from rwcrmhc11.comcast.net (rwcrmhc11.comcast.net [204.127.198.35]) by mx1.FreeBSD.org (Postfix) with ESMTP id BECE843D3F for ; Thu, 16 Sep 2004 18:19:14 +0000 (GMT) (envelope-from garycor@comcast.net) Received: from [10.56.78.111] (pcp09118143pcs.union01.nj.comcast.net[69.142.234.88]) by comcast.net (rwcrmhc11) with ESMTP id <20040916181913013008srrqe> (Authid: garycor); Thu, 16 Sep 2004 18:19:14 +0000 Message-ID: <4149DBCF.8010908@comcast.net> Date: Thu, 16 Sep 2004 14:30:39 -0400 From: Gary Corcoran User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040616 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Sam References: <41483C97.2030303@fer.hr> <4149D73C.5030309@comcast.net> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-hackers@freebsd.org Subject: Re: ZFS X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Sep 2004 18:19:15 -0000 Sam wrote: > On Thu, 16 Sep 2004, Gary Corcoran wrote: > >> Sam wrote: >> >>> On Thu, 16 Sep 2004, Jan Grant wrote: >>> >>>> On Thu, 16 Sep 2004, Sam wrote: >>>> >>>>> Let's suppose you generate an exabyte of storage per year. Filling >>>>> a 64-bit >>>>> filesystem would take you approximately 8 million years. >>>> >>>> >>>> >>>> Hang on, I'm not sure I know where these numbers are coming from. >>>> >>>> 1PB is - what? 2^50 bytes? That looks closer to 2^64 than your >>>> figures indicate. I'd imagine an exabyte a year ought to be topping out >>>> after 16 years. I'm missing about half-a-dozen orders of magnitude >>>> somewhere it seems. >>> >>> >>> >>> 1PB is indeed 2^50 bytes, but filesystems don't address on the byte, >>> but on the block (1K, 4K, 8k, ...). The numbers I'm using assume >>> the filesystem addresses on the sector, which is unrealistically >>> small. Jack it up to a 16K blocksize and you jump a few hundred >>> ZB in size. >> >> >> You have to be able to *seek* on a byte boundary. Hence doesn't a >> "64-bit" filesystem indeed mean "only" 2^64 bytes? > > > Only for the file you're seeking on. Yeah, okay, there's multiple definitions of what "64-bit filesystem" is referring to. So what are FreeBSD's current filesystem limitations? 2^64 bytes files, and 2^64 blocks per filesystem? But I seem to recall some problems as people were approaching a terabyte or two ??? Gary