Creating a File-Based LUN

Thick instant allocation

QTS allocates storage pool space when creating the LUN. This space is guaranteed to be available later.

Thin provisioning

QTS allocates storage pool space only when needed, such as when data is being written to the LUN. This ensures efficient use of space but there is no guarantee that space will be available.

LUN name

• Length: 1 to 32 characters

• Valid characters: 0-9, a-z, A-Z, underscore (_)

LUN capacity

Specify the maximum capacity of the LUN. The maximum capacity depends on the LUN allocation method:

• Thick provisioning: Equal to the amount of free space in the parent storage pool.

• Thin provisioning: 250 TB

Sector size

Changing the sector size to 4 KB increases LUN performance for specific applications and disk types.

Alert threshold

QTS issues a warning notification when the percentage of used LUN space is equal to or above the specified threshold.

Report volatile write cache for data safety

When enabled, QTS informs iSCSI initiators connected to this LUN that volatile write-cache is being used on the NAS. As a result, initiators might frequently tell QTS to flush cached LUN data to disk, which increases data safety but decreases LUN performance.

FUA bit support

When enabled, iSCSI initiators are able to tell QTS to flush important cached data to disk, instead of the whole read-write cache.