How many disk drives do you need for RAID 10?
The minimum number of disk drives needed for RAID 10? This depends on the storage array vendor's firmware. RAID 10 configurations can be accomplished by mirroring a stripe set, or striping a mirror set. When you stripe a mirror set (my preferred method due to resiliency), you first create two mirror sets and then create a stripe set from the two mirrors (minimum four drives), when you mirror a stripe set, you first create two stripe sets (usually of at least three drives each) and then mirror them to another stripe set (total of six drives).
I have not personally heard of creating a RAID 10 set from two drives, since two drives are the minimum for a simple mirror.
More on raid 10 minimum drives:
Double drive failures in a RAID 10 configuration
RAID 10: Two great RAIDs that go great together
03 Jan 2006