From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: ceph-disk disk partition alignment Date: Mon, 7 Mar 2016 13:37:37 +0530 Message-ID: <56DD36C9.9060406@redhat.com> References: <56CBEA15.4090309@dachary.org> <56CBF2DB.10602@dachary.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54870 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751958AbcCGIHt (ORCPT ); Mon, 7 Mar 2016 03:07:49 -0500 In-Reply-To: <56CBF2DB.10602@dachary.org> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Loic Dachary , Somnath Roy , ceph-devel On 02/23/2016 11:19 AM, Loic Dachary wrote: > Here it is http://tracker.ceph.com/issues/14842 > > On 23/02/2016 12:24, Somnath Roy wrote: >> eph-deploy is creating data partition from sector 1 ignoring what sgdisk is recommending (256 in my disk). Basically, it should be aligned with physical sector size (reported in /sys/block//queue/physical_block_size). In my case it is 16K physical and 4K logical...256 is perfectly fine as sgdisk/fdisk internally decides. >>> Disk performance will be severely impacted because of partitioning this way from ceph-deploy , I think that more modern partition tools handle alignment better (and handle the modern partition types) - sfdisk and parted both are better than fdisk I believe. For RHEL & Fedora, we try hard to make sure that we use the advertised alignment when we create a partition and default to an alignment on sector 2048 (1MB) if it is not set by the device. Ric