From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D56E31EB23 for ; Wed, 7 Feb 2024 22:39:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707345546; cv=none; b=l6BIEAAe24PA9g7hd+cxNC3Kg7d3CTWFHnbDUetO4Kw7zb1eK/NOtkDHO8ETJjaflNeNejX2YpM1BF7pFAaIwInppbBTUYu6R7JUwTSI2nK+F3V3/NUWbeJWREByCu7ucSINYC3thpkYV+YFJIy16qG3mf2bTDrrYzyeThAyOXY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707345546; c=relaxed/simple; bh=tjjD1i798u5ietaGRZCD1J6vQd1vhObMCyNbB997tJs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HIssvNsliUbvnubBxwHuzBN8joFVbqPJoUn08PQ4KDd8EtoeA22ekgXvLFIiMIuvvBS7Sbo2NwUawPD0BIGXG7/UIjtghVTcKOgFTOvuqIQg82GfVCVepd593EXHORXo/aEg9+fdKnG4mhAnJ0YsWf+2QrgQNwwJ2Ulwes3m0Cg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=F0rjd9V/; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="F0rjd9V/" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=tjjD1i798u5ietaGRZCD1J6vQd1vhObMCyNbB997tJs=; b=F0rjd9V/jjIOd/VwvgY/a/8AWo kFpYnsbVEgc8Xitln9s65QkT437iy2R4IsXB7Ka5X08dKyNCJjhvUkzphhe4VQEf8vwMnCUBJ1EVl 3wqlDFGgok3/DxwjGacce2DjiNfmpuGp6sbrbJdUJRO8PsoMrfks56US4x1sk8+SEkPCPLgBgfPJh mPdGo1G1/UzvYg/IMs/ZGgHOePnmKh0AA/KgQT8VfiypjxY6sLgnHnvo8rK+smSIxzsCDCI0PVzS5 4FxBfa4vG0Ao/03mHebPu3RVUcNNar9kCYFpxj8R5YW44w/Qy27jNRO9bkrlORtK/1YB8qKY2noR3 mTvZhBjw==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rXqZI-0000000GHCj-47OT; Wed, 07 Feb 2024 22:39:01 +0000 Date: Wed, 7 Feb 2024 22:39:00 +0000 From: Matthew Wilcox To: Luis Chamberlain Cc: linux-xfs@vger.kernel.org, ritesh.list@gmail.com, Pankaj Raghav , Daniel Gomez Subject: Re: Max theoretical XFS filesystem size in review Message-ID: References: Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Feb 07, 2024 at 02:26:53PM -0800, Luis Chamberlain wrote: > I'd like to review the max theoretical XFS filesystem size and > if block size used may affect this. At first I thought that the limit which > seems to be documented on a few pages online of 16 EiB might reflect the > current limitations [0], however I suspect its an artifact of both > BLKGETSIZE64 limitation. There might be others so I welcome your feedback > on other things as well. Linux is limited to 8EiB as loff_t is signed ... I don't want to introduce lllseek() to expand beyond 8EiB; I have reason to believe that we'll have 128-bit registers in relevant CPUs before we can buy reasonably priced arrays of drives that will reach 8EiB (and want to turn those into a single block device). See my Zettalinux presentation at Plumbers 2022 in Dublin (and that reminds me, I really should do something with zettalinux.org)