Every storage system must have a root volume. Therefore, you must always have one volume designated as the root volume. However, you can change which volume is used as the system's root volume.
The volume that you are designating to be the new root volume must meet the minimum size requirement. The required minimum size for the root volume varies, depending on the storage system model. If the volume is too small to become the new root volume, Data ONTAP prevents you from setting the root option.
In addition, the volume that you are designating to be the new root volume must have at least 2 GB of free space. It must also have a fractional reserve of 100%. The vol status –v command displays information about a volume’s fractional reserve.
If you use a FlexVol volume for the root volume, ensure that it has a guarantee of volume.
Starting in Data ONTAP 8.0.1, you can designate a volume in a 64-bit aggregate to be the new root volume.
If you move the root volume outside the current root aggregate, you must also change the value of the aggregate root option so that the aggregate containing the root volume becomes the root aggregate.
For storage systems with the root volume on the storage array, the array LUN used for the root volume must meet the minimum array LUN size for the root volume. For more information about the minimum array LUN size for the root volume, see the Hardware Universe at hwu.netapp.com.
If the volume does not have at least 2 GB of free space, the command fails and an error message appears.
After a volume is designated to become the root volume, it cannot be brought offline or restricted.
For more information about the aggregate root option, see the na_aggr(1) man page.
If you changed the root aggregate, a new root volume is created during the reboot when the aggregate does not already contain a FlexVol volume designated as the root volume and when the aggregate has at least 2 GB of free space.