RAID Type
Number of
Disks
Disk Failure
Tolerance
Capacity
Overview
RAID 5
≥ 3
1
Total combined disk
capacity minus 1
disk
• Data and parity information are
striped across all disks.
• The capacity of one disk is lost to
store parity information.
• Striping means read speeds are
increased with each additional
disk in the group.
• Recommended for a good
balance between data protection,
capacity, and speed.
RAID 6
≥ 4
2
Total combined disk
capacity minus 2
disks
• Data and parity information are
striped across all disks.
• The capacity of two disks are lost
to store parity information.
• Recommended for critical data
protection, business and general
storage use. It provides high disk
failure protection and read
performance.
RAID 10
≥ 4
(Must be an
even number)
1 per pair of
disks
Half of the total
combined disk
capacity
• Every two disks are paired using
RAID 1 for failure protection.
Then all pairs are striped
together using RAID 0.
• Excellent random read and write
speeds and high failure
protection, but half the total disk
capacity is lost.
• Recommended for applications
that require high random access
performance and fault tolerance,
such as databases.
RAID 50
≥ 6
1 per disk
subgroup
Total combined disk
capacity minus 1
disk per subgroup
• Multiple small RAID 5 groups are
striped to form one RAID 50
group.
• Better failure protection and
faster rebuild times than RAID 5.
More storage capacity than RAID
10.
• Better random access
performance than RAID 5 if all of
the disks are SSDs.
• Recommended for enterprise
backup with ten or more disks.
QTS 4.5.x User Guide
Storage & Snapshots
204
