Raid 5 Expansion - Logical Drive Expansion - Proliant Server

I added 2 72g scsi units to my existing array of 4. I have expanded
the array and the logical drive. Now the status says:


# 785 Background parity initialization is currently queued or in
progress on logical drive 1 ( RAID 5 in array A). If background parity
initialization is queued, it will start when I/O is performed on the
drive. When background parity initialization completes, the
performance of the logical drive will improve.

Do I have to wait to use DISKPART to utilize the unallocated space
showing in device manager? About how long should the process take?
Expanding took forever!

chaz