NFS hangs due to half-open TCP session
Applies to
- ONTAP
- NFS
- Firewall in between client and ONTAP
Issue
A client can experience this issue in various forms :
- Shell commands like
df
,ls
andumount
directed towards the NFS mountpoint hang indefintely and never finish running.- This might occur after network maintenance, or firewall maintenance, or rebooting client host
- A network event (such as a SVMDR cutover to new DNS servers) occurred, leaving stale NFS mounts
- Linux hosts experience NFS stale mounts randomly
- In a packet trace, ONTAP gets a TCP SYN packet from the client on an already established session.
- Client error message
"Server (server-name) not responding, still trying"