Hello Cheng,
At this time, it is not possible to export recordings. That feature might be added in the future but I am not sure when.
As you know, recordings are stored on the external NFS storage together with the system backup. As long as you have some sort of redundancy of your NFS storage your backups and recordings should be sage.
In case you want to move CWMS to a different location, ensure to move the NFS storage as well. As long as you redeploy CWMS and connect it to the same NFS storage, you will be able to restore from the backup and the links to all the recordings on the NFS storage will be restored as well.
Recordings can be saved indefinitely (as long as your NFS storage offers enough capacity).
I hope this answers your questions.
Thank you.
-Dejan
