From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 16 Jul 2007 17:59:08 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with SMTP id l6H0x0bm005839 for ; Mon, 16 Jul 2007 17:59:02 -0700 Date: Tue, 17 Jul 2007 10:58:54 +1000 From: David Chinner Subject: Re: raid50 and 9TB volumes Message-ID: <20070717005854.GL31489@sgi.com> References: <5d96567b0707160542t2144c382mbfe3da92f0990694@mail.gmail.com> <20070716130140.GC31489@sgi.com> <5d96567b0707160653m5951fac9v5a56bb4c92174d63@mail.gmail.com> <20070716221831.GE31489@sgi.com> <18076.1449.138328.66699@notabene.brown> <20070717001205.GI31489@sgi.com> <18076.4940.845633.149160@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <18076.4940.845633.149160@notabene.brown> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Neil Brown Cc: David Chinner , Raz , xfs-oss On Tue, Jul 17, 2007 at 10:54:36AM +1000, Neil Brown wrote: > On Tuesday July 17, dgc@sgi.com wrote: > > On Tue, Jul 17, 2007 at 09:56:25AM +1000, Neil Brown wrote: > > > On Tuesday July 17, dgc@sgi.com wrote: > > > > On Mon, Jul 16, 2007 at 04:53:22PM +0300, Raz wrote: > > > > > > > > > > Well you are right. /proc/partitions says: > > > > > .... > > > > > 8 241 488384001 sdp1 > > > > > 9 1 3404964864 md1 > > > > > 9 2 3418684416 md2 > > > > > 9 3 6823647232 md3 > > > > > > > > > > while xfs formats md3 as 9 TB. > .. > > > > > > If XFS is given a 6.8TB devices and formats it as 9TB, then I would be > > > looking at mkfs.xfs(??). > > > > mkfs.xfs tries to read the last block of the device that it is given > > and proceeds only if that read is successful. IOWs, mkfs.xfs has been > > told the size of the device is 9TB, it's successfully read from offset > > 9TB, so the device must be at least 9TB. > > Odd. > Given that the drives are 490GB, and there are 8 in a raid5 array, > the raid5 arrays are really under 3.5GB. And two of them is less than > 7GB. So there definitely are not 9TB worth of bytes.. > > mkfs.xfs uses the BLKGETSIZE64 ioctl which returns > bdev->bi_inode->i_size, where as /proc/partitions uses get_capacity > which uses disk->capacity, so there is some room for them to return > different values... Except that on open, it calls > bd_set_size(bdev, (loff_t)get_capacity(disk)<<9); > which makes sure the two have the same value. > > I cannot see where the size difference comes from. > What does > /sbin/blockdev --getsize64 > report for each of the different devices, as compared to what > /proc/partitions reports? And add to that the output of `xfs_growfs -n ` so we can see what XFS really thinks the size of the filesystem is. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group