QNAP

QTS 5.0.x

Thick, Thin, and Static Volumes

 

Volume Type

Static

Thick

Thin

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 be resized.

Very flexible

A volume can be resized. Also unused space can be reclaimed and added back into the parent storage pool.

Parent storage space

RAID group

Storage pool

Storage pool

Volumes allowed in 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, as 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

  • Add disks to the NAS

  • Replace existing disks with higher capacity disks

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