From owner-freebsd-questions@freebsd.org Mon Sep 4 20:48:38 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4D011E1D672 for ; Mon, 4 Sep 2017 20:48:38 +0000 (UTC) (envelope-from lcn@fastmail.net) Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 1F5A5190C for ; Mon, 4 Sep 2017 20:48:37 +0000 (UTC) (envelope-from lcn@fastmail.net) Received: from compute7.internal (compute7.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 8016120978 for ; Mon, 4 Sep 2017 16:48:36 -0400 (EDT) Received: from frontend2 ([10.202.2.161]) by compute7.internal (MEProxy); Mon, 04 Sep 2017 16:48:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastmail.net; h= content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to:x-me-sender:x-me-sender:x-sasl-enc :x-sasl-enc; s=fm1; bh=pL/B531nXlXpa66fH+SN30cQwJODE3t1XqMcP9Ld2 CE=; b=JpVDNJtiiGrew2ufoabKT5QtYh1FNfja7m0xaN5ZCfMuYSqTlyQiaOzbu n0LvC8jNgo+Ed1hgXOKZPHNsq8mkptrNgrONYOivDhmsobds2B7E44dX9WCAZ+eB 6ftH6OfZ6g7HDMg+8ughUrHnEyo1hXlU0SHWFb+8RILPoMdRAh9MPnvz5P4OD/a3 9n9CRzULIsxYB5+2z+UIBKiU5s7hHSfAr8JnIMtp6pQuzSfxx3JIdElgax/4Nm0E nqV6F1nhZwtlV3lfBeFVh8K21Acjs23mkrTPdzC/vKa3jmthstxcRK9OJEEjmYv2 7id0WuRGZZTrx8AR7hnCK1usgCYlQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-sender :x-me-sender:x-sasl-enc:x-sasl-enc; s=fm1; bh=pL/B531nXlXpa66fH+ SN30cQwJODE3t1XqMcP9Ld2CE=; b=gBkXjfHK8TMwP6m9smDQh74A/IVQGNc+IM CHw9mJi1z93Z3tLQYvjJ0rv1m3O8hs3J3x3TZlcMafAY5I+h/eLbQXayi9irGKFy Ka8WsRwd/gwUjesx3kaq+JNrjzGVtbmZqtNoTQ5OFg5qmdvQ85/VkgjlT/ZsmUXp rx8ynFxf9NRT7kpTnqlMLV4SbEw4Nbwmjndp3vkReRv99VCNNhWKgOliEq6X3TlZ 2n0KVVRqYZFxCBVQK3hPVxX4MI0VfgqLVtyrGXeA+CNDkBVsquSTVb6/+/umrkZ/ lo4STTXdaBoCRAqY3h17y3g6/Qfe/nzz0eRMjSfkxNJmLgfmlZ2w== X-ME-Sender: X-Sasl-enc: +kpaoXa/beM2MlAPWhVJ9bwvxeNw5j+oc26X+EWwaAUL 1504558116 Received: from [192.168.1.104] (109-170-180-151.xdsl.murphx.net [109.170.180.151]) by mail.messagingengine.com (Postfix) with ESMTPA id 169A924767 for ; Mon, 4 Sep 2017 16:48:35 -0400 (EDT) To: freebsd-questions@freebsd.org From: Louie Cardone-Noott Subject: Sector-size and advanced format (4k) disks Message-ID: <60623dab-3041-386d-4b19-9cc2e42c2424@fastmail.net> Date: Mon, 4 Sep 2017 21:48:34 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Sep 2017 20:48:38 -0000 Dear list, I searched the handbook, archives, and web but couldn't find a concrete answer to this. From what I can work out: 1. for compatibility, most HDDs these days present themselves as having 512 B logical / 4 k physical sectors 2. freebsd newfs (typically) sets a sector-size of 512 B and a fragment size of 4 k Some questions then please. First, is it optimal to force the sector size to 4 k to match the physical sector size, or is the default (point 2, above) fine? Second, how alarmed should I be that `man newfs` says setting the sector-size makes it impossible for fsck to find alternate superblocks? I thought partitioning with (say) 1 M alignment and invoking newfs with `-S 4096` would be best. True or false? Many thanks, Louie