On Mon, 18 Feb 2013, sk wrote:

i wait about 10 hours
and start after the resync process completed. 
it was not mount so i don't think there were any activity.

Well, then output from iostat -x 5 during the creation would be of 
interest. Also, try other filesystems such as xfs and see if that behaves 
differently.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se