From: Ted Ts'o Subject: Re: I/O topology fixes for big physical block size Date: Tue, 28 Sep 2010 16:57:41 -0400 Message-ID: <20100928205741.GA22257@thunk.org> 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> <4CA17B13.7080801@redhat.com> <20100928141545.GA21587@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Sandeen , Jens Axboe , "Martin K. Petersen" , "James.Bottomley@hansenpartnership.com" , "linux-scsi@vger.kernel.org" , "linux-ext4@vger.kernel.org" To: Mike Snitzer Return-path: Received: from thunk.org ([69.25.196.29]:34287 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752273Ab0I1U5v (ORCPT ); Tue, 28 Sep 2010 16:57:51 -0400 Content-Disposition: inline In-Reply-To: <20100928141545.GA21587@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Sep 28, 2010 at 10:15:45AM -0400, Mike Snitzer wrote: > Actually, -F allows one to override fs blocksize < physical_block_size. > > In this instance we have the following: > # cat /sys/block/dm-2/queue/physical_block_size > 1048576 > # cat /sys/block/dm-2/queue/logical_block_size > 512 > > > Should we change something? > > Unclear. I could see maybe automatically capping the fs block size at > 4096 if physical_block_size is larger and is a multiple of 4096? Can we decide soon what the right thing should be? I'm about to release e2fsrogs 1.41.13, and if I should put in some sanity checking code so mke2fs does something sane when it sees a 1M physical block size, I can do that. Or if the kernel is going to do that, it's fine too.... - Ted