HP EliteBook 2170p Notebook PC - Manual (Page 9)

Fault tolerance
Fault tolerance is the ability of a RAID array to withstand and recover from a drive failure. Fault
tolerance is provided by redundancy. Therefore, RAID 0 has no fault tolerance because it does not
copy data to another hard drive. With RAID 1 and Recovery, one drive can fail without causing the
array to fail. With Recovery, however, the restoration of a single file or an entire hard drive is much
simpler than with RAID 1 alone. With RAID 5, one of the three hard drives can fail without causing the
array to fail.
Performance
Performance is easy to understand, but it is difficult to measure because it involves several factors,
some of which are beyond the scope of this document. Overall storage performance is determined by
write performance and read performance, both of which vary based on the RAID technology selected.
● RAID 0 (striping) improves overall storage performance because data can be written and read
simultaneously across two hard drives.
● Recovery and RAID 1 (mirroring) writes the same data to both hard drives; therefore, write
performance may be slower. However, data can be read from both hard drives, so the read
performance can be higher than that of a single non-RAID hard drive.
● RAID 5 performs at a level between RAID 0 and RAID 1.
RAID modes supported 5