From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from ishtar.tlinx.org ([173.164.175.65]:59588 "EHLO Ishtar.sc.tlinx.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756478AbdKDJQm (ORCPT ); Sat, 4 Nov 2017 05:16:42 -0400 Received: from [192.168.3.12] (Athenae [192.168.3.12]) by Ishtar.sc.tlinx.org (8.14.7/8.14.4/SuSE Linux 0.8) with ESMTP id vA499pKX066100 for ; Sat, 4 Nov 2017 02:09:53 -0700 Message-ID: <59FD83DF.805@tlinx.org> Date: Sat, 04 Nov 2017 02:09:51 -0700 From: L A Walsh MIME-Version: 1.0 To: util-linux@vger.kernel.org Subject: what should blockdev getbpsz return 4k disks w/512e? Content-Type: text/plain; charset=UTF-8; format=flowed Sender: util-linux-owner@vger.kernel.org List-ID: I just tried blockdev on a HW raid device (/dev/sdb) composed of 4K disks that can (w/performance penalty) emulate 512 byte disk (i.e. have the 512e feature). It is returning 512. If the disk is composed of 4K disks, shouldn't the raid show 4K as well? Otherwise, how do utils know what alignment to use or not to use 512 due to penalty costs? For my formatted disks, I use 4K allocation units, so for those, I shouldn't see problems, but some other disk subsystems or raw-disk using progs also need to know to allocate on 4K boundaries. Any idea where this info should be showing up? Thanks! -linda