Disks need to be cleared if they were not zero'ed. Look at your disks (don't have the command handy) or look in filer view and I bet some are zero'ing.
 
From: Fletcher Cocquyt [mailto:fcocquyt@stanford.edu]
Sent: Friday, February 10, 2012 02:38 PM
To: toasters@teaparty.net <toasters@teaparty.net>
Subject: tracking aggr initialization progress ?
 
Is there a way to track the progress (% complete?) for aggr creation/initialization?

aggr status
           Aggr State           Status            Options
          aggr1 creating        raid_dp, aggr     raidsize=20, 
                                initializing      snapshot_autodelete=off, 
                                32-bit            lost_write_protect=off

thanks

Fletcher