Why do NFSv4 and NFSv4.1 I/O stop while a takeover/giveback, an aggregate relocation occur, or a VFiler Migration?
Applies to
- ONTAP 9
- Data ONTAP 7-mode
- NFSv4
Answer
- I/O stops when a storage system serving data over NFSv4 to clients is in a takeover/giveback mode or when an operation such as an aggregate relocation is performed.
- NFSv4.x is a stateful protocol similar to SMB/CIFS.
- A short outage is expected anytime you change the interface you are connected to while using stateful protocols.
- If data is being served on NFSv3, this behavior is not seen since NFSv3 is a stateless protocol.
- Applications are expected to recover during grace period
Additional Information
Related Links:
- Network File System (NFS) version 4 Protocol RFC 3530
- Specifying the NFSv4 locking grace period
- BUG 669560: NFS clients unable to get locks due to aggregates stuck in grace state