Clustered Data ONTAP 8
Data ONTAP 7 and earlier
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.
If data is being served on NFSv3, this behavior is not seen since NFS v3 is a stateless protocol. In NFSv4 and later, NFS is similar to CIFS such that it is now a stateful protocol. A short outage is expected anytime you change the interface you are connected to while using stateful protocols.
- 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