User guide

Compaq StorageWorks RAID Array 4000 User Guide
67% to 93% 67% to 93% 50% 100%
(n-1)/n (n-1)/n n/2 n
Parity
distributed
over each
drive
Dedicated
parity drive
Duplicate
data
None
3321
Tolerant of
single drive
failures.
Higher
performance
than RAID 4.
Uses the
least
amount of
storage
capacity for
fault
tolerance.
Tolerant of
single drive
failures.
Like RAID 5,
uses the
least
amount of
storage
capacity for
fault
tolerance.
Tolerant of
multiple,
simultaneous
drive failures.
Higher
performance
than RAID 4 or
5. Uses the
most storage
capacity for
fault tolerance.
Requires an
even number
of drives.
Best
performance
but data is
lost if any
drive in the
logical drive
fails. Uses
no storage
space for
fault
tolerance.
* All drives are the same capacity
If you require a fault-tolerant system for critical data, Compaq recommends
using RAID 5 for maximum storage space efficiency, or RAID 1 if I/O
performance is more important.