From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bryn M. Reeves" Subject: Re: Simulating faulty disk Date: Fri, 21 Oct 2011 15:56:27 +0100 Message-ID: <4EA1881B.5070607@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> 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: <4EA18610.3050900@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 03:47 PM, Yathindra wrote: > dmsetup create d0 --table="0 `blockdev --getsize /dev/sdb` delay > /dev/sdb 0 500" > dmsetup create f0 --table="0 `blockdev --getsize /dev/mapper/d0` flakey > /dev/mapper/d0 0 9 1" > mkfs -t ext3 /dev/mapper/f0 > ... > ... > ext2fs_mkdir: Attempt to read block from filesystem resulted in short > read while creating root dir > > Can we even mount such a device ? It's a flakey device :) With that table you'll have a device that is failing write I/Os for 1s in every ten. If that coincides with mkfs trying to write to the device it will create a corrupted file system. Depending on what you are trying to test you may want to put data on the device first. Regards, Bryn.