[dm-devel] Simulating faulty disk

[Yathindra]

Is there any way we can create a regular scsi device and then 
dynamically change its personality
to delay or flakey ?
Or
Is there a way to dynamically change the parameters of flakey/delay device.

So we can start with no errors and then we can inject some errors.

Thanks,
Yathi

On 10/21/2011 9:21 AM, Bryn M. Reeves wrote:
> 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.