Slow NFS but SMB and local access are fast

[tt2468]

I am having a similar issue, this happened to me since I upgraded from FreeNAS 11(Latest) to TrueNAS(Lates). NFS client writes start out super fast, then come to a crawl after several seconds. I tested writing to the zpool locally(no issues), the CIFS writes from 3 different machines(Linux[no issues]/Windows[no issues]), but NFS writes from one host not only slow down but they start timing out all actions from all of my NFS mounts on multiple servers. The NFS timeouts from multiple hosts on my monitoring system(check_mk) is the way I found this issue.

I suspect there is a bug somewhere in the NFS daemon.

Just stumbled across this. I think I'm having the exact same issue. Proxmox nodes accessing NFS. The storage server is running a solid raidz2 of 5x 16TB CMR drives, over 10Gb networking. Everything seems OK but after a long transfer NFS slows to an unusable crawl on all Proxmox nodes at once, while disk read/write tests and iperf via the Truenas terminal work perfectly fine. Might need to switch to linux for storage since it seems like there may not be a good fix.