From owner-freebsd-stable@FreeBSD.ORG Thu Sep 11 08:01:38 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 0119D592 for ; Thu, 11 Sep 2014 08:01:37 +0000 (UTC) Received: from isis.morrow.me.uk (isis.morrow.me.uk [204.109.63.142]) by mx1.freebsd.org (Postfix) with ESMTP id CE2CEDF8 for ; Thu, 11 Sep 2014 08:01:36 +0000 (UTC) Received: from anubis.morrow.me.uk (unknown [93.89.81.46]) (Authenticated sender: mauzo) by isis.morrow.me.uk (Postfix) with ESMTPSA id 7927145088; Thu, 11 Sep 2014 07:23:56 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.8.3 isis.morrow.me.uk 7927145088 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=morrow.me.uk; s=dkim201101; t=1410420236; bh=nrxDZC6KsaoQ+UgBTmRRfdQ1D0YkwHSx83k57VNGpG8=; h=Date:From:To:Subject:References:In-Reply-To; b=xWS2hMG+qIHTZOsdmAaDvVc0y9zUrL1xyukafPSykDt34EFezyJcJoOmQ3nFWjzus oDUR+VGWI99ebD58tcjEtOmwU81wO2W0dyQf1NqMpOnoQSwChha1ptb4pHKqKF1Kez auUeXoL6BhTNzgSrqE6qWczJTTgS5X9KT5o4eBeU= X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.98.1 at isis.morrow.me.uk Received: by anubis.morrow.me.uk (Postfix, from userid 5001) id D28A3153E0; Thu, 11 Sep 2014 08:23:54 +0100 (BST) Date: Thu, 11 Sep 2014 08:23:54 +0100 From: Ben Morrow To: karl@denninger.net, freebsd-stable@freebsd.org Subject: Re: getting to 4K disk blocks in ZFS Message-ID: <20140911072351.GA50786@anubis.morrow.me.uk> Mail-Followup-To: karl@denninger.net, freebsd-stable@freebsd.org References: <540FF3C4.6010305@ish.com.au> <54100258.2000505@freebsd.org> <5410F0B4.9040808@ish.com.au> <54114029.3060507@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54114217.9040403@denninger.net> X-Newsgroups: gmane.os.freebsd.stable User-Agent: Mutt/1.5.23 (2014-03-12) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Sep 2014 08:01:38 -0000 Quoth Karl Denninger : > On 9/11/2014 1:24 AM, Andriy Gapon wrote: > > On 11/09/2014 04:22, Steven Hartland wrote: > >> ----- Original Message ----- From: "Aristedes Maniatis" > >>> Should the FreeBSD project change this minimum in the next release? > >>> There seems to be no downside and a huge amount of pain for people > >>> who stumble along with the defaults not knowing what a mess they are > >>> creating to solve later. > >> > >> The downside is wasted space which can be significant and hence when > >> I last suggested just this it was unfortunately rejected. > >> > >> We still maintain a local patch to our source tree which does just > >> this because, as you've mentioned, we don't want the pain so its > >> easier to just run everything as 4k. > > > > Another downside is 1/4th of uberblocks, 32 vs 128. Also, automatic > > sector size detection works great for me and I've never had a need > > to manually tweak ashift. > > > It works great until you start replacing older disks with new, larger > ones and find out that the new ones are 4k where the old ones were not..... Is there any way (short of building a new pool) to get a reasonable idea of how much extra space a given pool would use if converted? Ben