FlexVol volumes are always associated with one Storage Virtual Machine (SVM), and one aggregate that supplies its storage. The SVM can limit which aggregates can be associated with that volume, depending on how the SVM is configured.
When you create a FlexVol volume, you specify which SVM the volume will be created on, and which aggregate that volume will get its storage from. All of the storage for the newly created FlexVol volume comes from that associated aggregate.
If the SVM for that volume has aggregates assigned to it, then you can use only one of those assigned aggregates to provide storage to volumes on that SVM. This can help you ensure that your SVMs are not sharing physical storage resources inappropriately. This segregation can be important in a multi-tenancy environment, because for some space management configurations, volumes that share the same aggregate can affect each other's access to free space when space is constrained for the aggregate. Aggregate assignment requirements apply to both cluster administrators and SVM administrators.
Volume move and volume copy operations are not constrained by the SVM aggregate assignments, so if you are trying to keep your SVMs on separate aggregates, you must ensure that you do not violate your SVM aggregate assignments when you perform those operations.
If the SVM for that volume has no aggregates assigned to it, then the cluster administrator can use any aggregate in the cluster to provide storage to the new volume. However, the SVM administrator cannot create volumes for SVMs with no assigned aggregates. For this reason, if you want your SVM administrator to be able to create volumes for a specific SVM, then you must assign aggregates to that SVM.
Changing the aggregates assigned to an SVM does not affect any existing volumes. For this reason, the list of aggregates assigned to an SVM cannot be used to determine the aggregates associated with volumes for that SVM.