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QTS RAID type comparison

Last modified date: 2024-10-14

Applicable Products

QTS

Details

QTS supports several RAID types. Each type provides a different combination of striping and redundancy.

Important
  • For best performance and space efficiency, when creating a RAID group, you should use disks of the same brand, same disk type (all HDD, all SSD, or all SAS), and same capacity.
  • If different types of disks are combined in one RAID group, the RAID group will function according to the speed of the slowest disk.
  • If disks with different capacities are combined in one RAID group with disk failure tolerance, all disks function according to the capacity of the smallest disk.
    For example, if a RAID group contains five 2 TB disks and one 1 TB disk, QTS detects six 1 TB disks.
  • If you mix disks of different capacities, QNAP recommends the following:
    1. Create a separate RAID group for each capacity.
    2. Combine the RAID groups using storage pools.
  • Increasing the number of disks in a RAID group increases the risk of simultaneous disk failure and lengthens rebuild times.
    For example, a RAID group with 24 drives is 20 times more likely to fail with RAID 6 than with RAID 60. When creating a storage pool with a large number of disks, you should split the disks into sub-groups using RAID 50 or RAID 60.
RAID TypeNumber of DisksDisk Failure ToleranceCapacityOverview
Single10Capacity of the one disk
  • Uses a single disk for storage.
  • Provides no disk failure protection or performance benefits.
  • Suitable for single disk configurations that have a data backup plan in place.
JBOD (just a bunch of disks)2 or more0Total combined disk capacity
  • Combines disks together in a linear fashion. QTS writes data to a disk until it is full before writing to the next disk.
  • Uses the total capacity of all the disks.
  • Not a real RAID type. It provides no disk failure protection or performance benefits.
  • Unless you have a specific reason to use JBOD, you should use RAID 0 instead.
RAID 02 to 160Total combined disk capacity
  • Disks are combined together using striping.
  • RAID 0 offers the fastest read and write speeds, and uses the total capacity of all the disks.
  • Provides no disk failure protection. This RAID type must be paired with a data backup plan.
  • Recommended for high-performance applications such as video editing.
RAID 121Half of the total combined disk capacity
  • An identical copy of data is stored on each disk.
  • Half of the total disk capacity is lost, in return for a high level of data protection.
  • Recommended for NAS devices with two disks.
RAID 53 to 161Total 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 64 to 162Total 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 104 to 16
(Must be an even number)		1 per pair of disksHalf 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 506 to 30
1 per disk subgroupTotal 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.
RAID 608 to 30
2 per disk subgroupTotal 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.

Resources

QNAP RAID Calculator

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