Install RAID1 without Second Hard Drive?

Question

HP P410i Raid Card.

I am waiting for a second hard drive to arrive.

Is it possible to start with 1 hard drive and enable RAID1 without loosing data when the second drive is installed?

Answer 1

Yes, you just create a single logical volume and can later migrate the RAID level to R1 (though R6 needs a paid additional licence sometimes).

Answer 2

Yes, this is possible and fully supported. A few things will help us give you a more specific answer.

• What operating system are you using? This matters if you wish to perform the migration to RAID 1 while the system is running because you'll need the HP management tools installed in order to do this.
• What server model is this? Just in case there are quirks with your particular model. More information is always better.
• Do you have a battery-backed cache (BBWC) or flash-backed cache (FBWC) module installed on the controller? Transformations of existing arrays can only be performed if an FBWC or BBWC unit is attached to the controller.

This is officially called an "Array Transformation". In order to run it, you either need the HP Array Configuration Utility installed within your operating system, or you need to use a bootable CD/DVD like the HP SmartStart CD, the HP Support Pack for ProLiant or the Offline Array Configuration Utility.

If all of those prerequisites are met, you should be able to run the array transformation without incident. Allow 15 minutes per gigabyte for the transformation.

If you can wait for the other drive, the complexity of the operation will be reduced significantly... I would probably wait if you're unsure or are not prepared to use the tools listed above.