This article discusses over-provisioning an SSD
Essentially the article indicates two methods for over-provisioning:
1) Using the SET MAX ADDRESS command
2) Defining a partition that is smaller than the capacity of the drive
I'm wondering if, in a RAID 0 configuration, there isn't a THIRD option that achieves this as well, and that is defining a RAID array that is smaller than the sum of the two drives.
In my situation I have two x25v 40GB SSD's in a RAID 0, so if for example I defined a RAID 0 array at 60GB does this achieve the same thing as options 1 or 2 and will the SSD's see this unused portion and use it?
There is another way for over-provisioning as well.... just don't fill the drive up!
IMO, this is the best way since it allows the greatest flexibility. Sometimes, you may temporarily need that extra space. You can set a quota in the OS to warn you if you exceed a subjective limit. An enforced over-provisioning is really only needed if you have some unmanaged servers.
However, you are correct. If you create a 60GB parition on a 80GB array, that would be a 20GB over-provisioning (which is excessive for common desktop usage).