RAID 5, also known as distributed parity, seeks to gain reliability, like
mirroring, with lower cost. RAID 5 is like RAID 0—striping, to get a
larger volume—but with a single additional disk used to store recovery
information. If a single disk fails, the RAID 5 set continues to work.
When the failed disk is replaced, the data on that disk is rebuilt, using
the recovery disk. Performance is reduced during the rebuild. RAID 5
gives increased read speed, as with RAID 0. However, writes can take
longer, as creating and writing the recovery information requires reading
information on all the other disks.