You can make a copy of a LUN or create a point‑in‑time clone of a LUN. When creating a copy, you copy all of the LUN data to the new LUN. You also have the option to copy the LUN properties to a new LUN without copying the source data.
Create a Clone LUN when you want to create an exact image of the original LUN. A Clone LUN is a point‑in‑time, read‑write copy of a LUN that you can immediately use. A Clone LUN retains the same QoS parameters as the source LUN and consumes storage capacity from the Clone LUN storage space created for the source LUN. A Clone LUN only stores the differences between the source LUN and the clone. The Clone LUN uses the source LUN for most data. A Clone LUN is available immediately after creation. Clone LUNs provide a convenient method to branch from the source data without the need to do a full block‑level copy.
Another reason to create a clone or a copy is to preserve a point-in-time view of the data. If you create a clone for this purpose, you can later restore the data to the source LUN.
Copy a LUN when you need a new LUN with the same starting data as an existing LUN.
Before creating a Clone LUN or a copy of a LUN, ensure that changes to the source LUN are minimized. For best results, pause the host applications that access the LUN, or use host software, such as Oracle FS Volume Shadow Copy Service Provider (VSS), before creating the Clone LUN. When the system displays the replica in the Oracle FS System Manager (GUI), you can resume writing to the LUN.
Unlike a clone, the new blocks for the copy might be on a different drive group or on a drive group of a different Storage Class. For example, a volume copy of a LUN that uses a high performance Storage Class, such as a Performance solid-state drive, premium priority LUN may be created in a low performance Capacity drive.
You can also create a LUN that has the QoS and storage capacity settings of an existing LUN. Creating a LUN in this manner copies the properties of the LUN without copying the associated data. After you create a LUN with the desired properties, you can use the LUN as a template for creating new LUNs.