From: Eric Sandeen Subject: Re: I/O topology fixes for big physical block size Date: Tue, 28 Sep 2010 00:20:19 -0500 Message-ID: <4CA17B13.7080801@redhat.com> References: <1285605664-27027-1-git-send-email-martin.petersen@oracle.com> <4CA0CC38.5010804@fusionio.com> <4CA118FF.1080100@fusionio.com> <20100927231551.GA15653@redhat.com> <4CA16F6A.1090904@fusionio.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Mike Snitzer , "Martin K. Petersen" , "James.Bottomley@hansenpartnership.com" , "linux-scsi@vger.kernel.org" , "linux-ext4@vger.kernel.org" To: Jens Axboe Return-path: Received: from mx1.redhat.com ([209.132.183.28]:17718 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767Ab0I1FU0 (ORCPT ); Tue, 28 Sep 2010 01:20:26 -0400 In-Reply-To: <4CA16F6A.1090904@fusionio.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Jens Axboe wrote: > On 2010-09-28 08:15, Mike Snitzer wrote: >> On Mon, Sep 27 2010 at 6:36pm -0400, >> Martin K. Petersen wrote: >> >>>>>>>> "Jens" == Jens Axboe writes: >>> Jens> Does mkfs do the right thing? >>> >>> Depends on which mkfs it is. Mike has tested things and can chip in >>> here... >> I haven't test all mkfs.* but... >> >> mkfs.xfs just works with 1M physical_block_size. >> >> mkfs.ext4 won't by default but -F "fixes" that: >> >> # mkfs.ext4 -b 4096 -F /dev/mapper/20017380023360006 >> mke2fs 1.41.12 (17-May-2010) >> Warning: specified blocksize 4096 is less than device physical sectorsize 1048576, forced to continue > > OK, so that's not exactly doing the right thing, but at least you can > work around it with a parameter. So I'd say that is good enough. Which part of it is the wrong thing...? Today mkfs.ext4 refuses to create an fs blocksize which is smaller than logical or physical by default, because one is suboptimal and the other is impossible. -F (force) can override the suboptimal fs blocksize < logical blocksize case... Should we change something? Thanks, -Eric >> I'll check fdisk and parted tomorrow (I know lvm2 doesn't look at >> physical_block_size). > > Thanks! >