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On 12/26/2013 01:56 AM, cosmos cosmos wrote:
> Hello.
>
> My name is Rucia for Samsung SDS.
>
>
> I had in truouble in volume deleting.
>
> I am developing for supporting big data storage such as hadoop in lvm.
>
>
> it use as a full disk io for deleting of cinder lvm volume because of dd
> the high disk I/O affects the other hadoop instance on same host.
>
>
> If using dd for deleting the volume,  it takes too much time for
> deleting of cinder lvm volume because of dd.
>
> Cinder volume is 200GB for supporting hadoop master data.
>
> When i delete cinder volume in using 'dd if=/dev/zero of $cinder-volume
> count=1000000 bs=1M' it takes about 30 minutes.

While I think your ionice proposal makes some sense, I think it would be 
better to avoid the cost of the volume wipe on deletion in the first place.

I read a proposal about using thinly-provisioned logical volumes as a 
way around the cost of wiping the disks, since they zero-fill on demand 
rather than incur the cost at deletion time.

Chris