Hello muabdib, The rebuild time can vary for the MD3200, & there is no way of confirming that it will finish in the window that you stated that you have.  With only having 48 hours to do the expansion I would suggest is that if you have a place to backup all of your data to that you backup all the data and then destroy it then recreate it.  Once it has been recreated then restore data to the group.   Please let us know if you have any other questions.
Hi: I  have a MD3200 with a RAID-5 disk group with 4 SAS 15k 600 GB disks. I want to expand this RAID-5 with another two SAS 15k 600 GB disks. I know that the MD3200 can do it online and with the two disks at the same time, but as far as I have a not very good performance in this disk group (this is the reason why I'm going to expand the RAID-5 volume) I'll try to do it this weekend with all systems disconected from the MD3200. The question is how much it takes to rebuild the disk group completly? Actually there are 1,5 TB of data (virtual machine disks) in the disk group, and I want to ensure that 48 hours si sufficient for this operation. Thanks.
Disk Group Rebuild