"Disk mirroring uses two drives at a time and duplicates exactly
one drive to the other. This duplication provides hardware
redundancy; if one drive fails, the other can continue to operate
independently. Software errors can propagate across the mirror,
however, corrupting both disks...
"Level 5 stripes data and the error correcting parity data
across all the disks in the array. As a result, one disk can fail
without loss of data. When this happens, the RAID is said to be
operating in degraded mode. If more than one disk fails at the same
time, though, the entire array will fail.
"This article focuses on using software RAID Level 5 under a
fresh installation of Red Hat 8.0 and testing the fault tolerance
of the RAID. RAID support for Linux has matured over the years, and
the ability to install a system that can boot into a
RAID-configured set of disks is standard..."