RAID Type
Number of
Disks
Disk Failure
Tolerance
Capacity
Overview
RAID 60
≥ 8
2 per disk
subgroup
Total combined disk
capacity minus 2
disks per subgroup
• Multiple small RAID 6 groups are
striped to form one RAID 60
group.
• Better failure protection and
faster rebuild time than RAID 6.
More storage capacity than RAID
10.
• Better random access
performance than RAID 6 if all of
the disks are SSDs.
• Recommended for business
storage and online video editing
with twelve or more disks.
RAID Group Status
Status
Description
Ready
The RAID group is working normally.
Degraded
One or more disks in the RAID group have failed. The number of disk failures
are within the disk failure tolerance of the RAID group. There are not enough
spare disks available to QTS to replace all the failed disks.
Degraded (Rebuilding)
One or more disks in the RAID group have failed. The number of disk failures
are within the disk failure tolerance of the RAID group. QTS has replaced the
failed disks with spare disks, and is now rebuilding the RAID group.
Not active
One or more disks in the RAID group have failed. The number of disk failures
exceeds the disk failure tolerance of the RAID group.
RAID Disk Failure Protection
All RAID types except for RAID 0 can tolerate a specific number of disk failures without losing data. When a
disk in a RAID group fails, the RAID group status changes to
degraded
and then QTS performs one of the
following actions.
Spare Disk Available
Actions
Yes
• QTS automatically replaces the failed disk with a spare disk and then
starts rebuilding the RAID group.
• The status of the RAID group changes to
rebuilding
, and then
changes back to
Ready
after rebuilding has finished.
No
You must replace the failed disk manually. QTS starts rebuilding the RAID
group after you have installed a working disk.
Configuring a RAID Group Hot Spare
Assigning a hot spare gives extra protection against data loss. In normal conditions, a hot spare disk is
unused and does not store any data. When a disk in the RAID group fails, the hot spare disk automatically
replaces the faulty disk. QTS copies the data to the spare disk in a process called RAID rebuilding.
QTS 4.5.x User Guide
Storage & Snapshots
205