A volume is a portion of storage space within the NAS. Each volume is created from the storage space of a storage pool, or of a RAID group. Volumes are used to divide and manage your storage space. QNAP NAS devices support three different types of volume.
|
Volume Type |
|||
|---|---|---|---|
|
Single Static |
Thick Multiple |
Thin Multiple |
|
|
Summary |
Best overall read/write performance, but does not support most advanced features |
Good balance between performance and flexibility |
Enables you to allocate storage space more efficiently |
|
Read/write speed |
Fastest for random writes |
Good |
Good |
|
Flexibility |
Inflexible A volume can only be expanded by adding extra drives to the NAS. |
Flexible A volume can easily grow in size. |
Very flexible A volume can easily grow in size, and unused space can be reclaimed and added back to the parent storage pool. |
|
Parent storage space |
RAID group |
Storage pool |
Storage pool |
|
Number of volumes that can be created in the parent storage space |
One |
One or more |
One or more |
|
Initial size |
Size of the parent RAID group |
User-specified |
Zero Storage pool space is allocated on-demand, data is written to the volume. This is called thin provisioning. |
|
Maximum size |
Size of the parent RAID group |
Size of the parent storage pool |
Twenty times the amount of free space in the parent storage pool The size of a thin volume can be greater than that of its parent storage pool. This is called over-allocation. |
|
Effect of data deletion |
Space is freed in the volume |
Space is freed in the volume |
QTS can reclaim the space and add it back into the parent storage pool. |
|
Method of adding storage space |
|
Allocate more space from the parent storage pool |
Allocate more space from the parent storage pool |
|
Snapshot support (fast backup and recovery) |
No |
Yes |
Yes |
|
Qtier (automatic data tiering) support |
No |
Yes |
Yes |