Limitations

Velero doesn't overwrite objects in-cluster if they already exist.
Velero supports a single set of credentials per provider. It's not yet possible to use different credentials for different object storage locations for the same provider.
Volume snapshots are limited by where your provider allows you to create snapshots. For example, AWS and Azure do not allow you to create a volume snapshot in a different region than where the volume is located. If you try to take a Velero backup using a volume snapshot location with a different region than where your cluster's volume is, the backup will fail.
It is not yet possible to send a single Velero backup to multiple backup storage locations simultaneously, or a single volume snapshot to multiple locations simultaneously. However, you can set up multiple backups manually or scheduled that differ only in the storage locations.
Cross-provider snapshots are not supported. If you have a cluster with more than one type of volume (e.g. NFS and Ceph), but you only have a volume snapshot location configured for NFS, then Velero will only snapshot the NFS volumes.
Restic data is stored under a prefix/subdirectory of the main Velero bucket and will go into the bucket corresponding backup storage location selected by the user at backup creation time.
When performing cluster migration, the new cluster number of nodes should be equal or greater than the original cluster.

For more information about storage and snapshot locations, refer to Velero: Backup Storage Locations and Volume Snapshot Locations.