Joined: 14 Mar 2007 Posts: 8657 Location: Back in jolly old England
I would like to add that in the referred post, it is said that the secondary allocation can be satisfied by up to three extents.
This was changed a lot of years ago to be five extents. So in effect if you allocate your dataset on a fragmented volume, e.g. (CYL(100,100),RLSE)it may take 5 extents to satisfy the primary allocation, a further five for the first secondary, five more for the second secondary, and Sx37 when attempting to add the third secondary allocation.