From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bryn M. Reeves" Subject: Re: Simulating faulty disk Date: Fri, 21 Oct 2011 16:21:23 +0100 Message-ID: <4EA18DF3.3000800@redhat.com> References: <4E9F9321.8090704@cs.utah.edu> <4E9FE97E.4030209@redhat.com> <4EA04201.1050702@cs.utah.edu> <4EA044A9.6070406@redhat.com> <4EA05072.10107@cs.utah.edu> <4EA05D0A.7030909@redhat.com> <4EA06020.9000708@cs.utah.edu> <4EA13A52.60902@redhat.com> <4EA18610.3050900@cs.utah.edu> <4EA1881B.5070607@redhat.com> <4EA188F3.4000206@cs.utah.edu> <4EA18C11.5060600@cs.utah.edu> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4EA18C11.5060600@cs.utah.edu> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Yathindra Cc: device-mapper development List-Id: dm-devel.ids On 10/21/2011 04:13 PM, Yathindra wrote: > >mount -t ext3 /dev/sdb /mnt > Copied some data into /mnt > >dmsetup create d0 --table="0 `blockdev --getsize /dev/sdb` delay > /dev/sdb 0 500" > device-mapper: reload ioctl failed: Invalid argument > Command failed You can't create a mapped device on something while it is mounted as device-mapper needs to open it exclusively. > But as seen from above, dmsetup is failing to create a flakey/delay > device when /dev/sdb > has a filesystem on top of it. Is there any workaround ? Set up the file system the way you want it on sdb first. Then unmount it and create the device-mapper devices and mount that. Regards, Bryn.