Question : Problem: Expanding RAID 1 + 0 on a HP Proliant ML350 G4

What's the best way to expand storage space on a HP Proliant ML 350 G4 with a RAID 1 + 0.  It's currently only listing two physical drives which is a bit confusing, because I thought you need four for RAID 1 + 0.  I copied this from Array Configuration Utility 7.15.19.0.  Thanks!

Controller  Smart Array 641 Controller
Bus Interface  64-Bit PCI  
Controller Location  Slot 3
 
RAID ADG status  Disabled  
Hardware Revision  B
Firmware Version  2.26
Rebuild Priority  Low  
Expand Priority  Low  
Current Surface Scan Delay  15 sec
Number of Arrays  1
Number of Logical Drives  1
Number of Physical Drives  2
Physical Drives Attached to Port 1 SCSI ID 0, 72.8 GB (Parallel SCSI)
SCSI ID 1, 72.8 GB (Parallel SCSI)
 
All Physical Drives Assigned  Yes  
 
Array Accelerator  
Present  Yes  
Cache Status  Enabled  
Accelerator Ratio  100% Read /0% Write  
Total Memory on Controller  64 MB  
Battery Pack Count  0

Answer : Problem: Expanding RAID 1 + 0 on a HP Proliant ML350 G4

Technically you do need more than two drives for RAID 1+0 but it's just terminology, functionality is the same, they also call a single drive on it's own RAID 0 which isn't quite correct.

Add your two new drives (can do that when powered on) and go into the ACU, click on configuration wizards and there should be an Expand Drive Array wizard, it will ask you which unassigned drives to add to the array and the rest is obvious. You can also click on the ? in the top right to get the help menu and under arrays: how to is expand drive array help with a flash demo that I've never been able to get to work.