Understanding RAID level-1

RAID level-1 provides 100% data redundancy and requires only two hard disk drives. With RAID level-1, the first half of a stripe is the original data; the second half of a stripe is a mirror (that is, copy) of the data, but written to the other drive in the RAID level-1 array.

Because the data is mirrored, the capacity of the logical drive when assigned RAID level-1 is 50% of the array capacity.

RAID level-1 example

You have two physical drives.
Create an array with the physical drives.
Then, create a logical drive within the array.

The data is striped across the drives, creating blocks.

Notice that the data on the right drive is a mirror copy of the data on the left drive.

With RAID level-1, if one of the hard disk drives fails, the ServeRAID controller switches read and write requests to the remaining functional drive in the RAID level-1 array.

See also

Selecting a RAID level
RAID level-0
RAID level-1 Enhanced
RAID level-5
RAID level-5 Enhanced