Operation Manual

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as a target.
An iSCSI LUN (Logical Unit Number) is a logical volume mapped to the iSCSI target and
there are two types of LUNs: file based LUN and block based LUN.
The file based LUN is the legacy LUN, while the block based LUN is available for certain
NAS models. Please refer to the product comparison table for details.
The table below lists the features supported by block based LUNs and file based LUNs:
Block-based LUN
(recommended)
File-based LUN (Legacy)
VAAI Full Copy
Supported
Supported
VAAI Block Zeroing
Supported
Supported
VAAI Hardware Assisted
Locking
Supported
Supported
VAAI Thin Provisioning and
Space Reclaim
Supported
Not Supported
Thin Provisioning
Supported
Supported
Space Reclamation
Supported (with VAAI or
from Windows 2012 or 8)
Not Supported
Microsoft ODX
Supported
Not Supported
LUN Backup
Not Supported Yet
Supported
LUN Snapshot
Not Supported Yet
1 Time Snapshot
Please note that in general, better system performance can be achieved through block
based LUNs, and hence, it is recommended to use block based LUNs whenever possible.
There are two methods a LUN can be allocated: Thin Provisioning and Instant Allocation:
Thin Provisioning: Allocate the disk space in a flexible manner. The disk space can be
allocated to the target anytime regardless of the current storage capacity available
on the NAS. Over-allocation is allowed as the storage capacity of the NAS can be
expanded using online RAID capacity expansion.
Instant Allocation: Allocate the disk space to the LUN instantly. This option
guarantees the disk space assigned to the LUN but may require more time to create
the LUN.