Completed reconfiguring the external RAID array attached to FW0 under WP 4158, to match the configuration on FW1.  (Note that I had the two FW designations reversed in the original work permit text - it was in fact FW0 that was reconfigured, FW1 was untouched.)  It took approximately 3.5 hours to backup the minute trends to the SATABoy, with the SSD filesystem at 40% utilization.  For a nearly full SSD filesystem, expect the backup to take the better part of a day.