NFS issues since upgrading to 13-RELEASE

[Allan Jude]

On 4/15/2021 9:22 AM, Chris Roose wrote:
> I posted this in -questions and someone suggested I post here as well.
> 
> I'm having NFS availability issues between my Proxmox client and FreeBSD server (10G link) since upgrading to 13-RELEASE. And unfortunately I upgraded my ZFS pool to v2.0.0 before I noticed the issue, so I'm kind of stuck.
> 
> Periodically, the NFS server (I've tried both v3 and v4.2 clients) will go unresponsive for several minutes. I never had this problem on 12.2, and as far as I can tell it's not a disk or network I/O issue. I'll get several "nfs: server not responding, still trying" messages on the client and a few minutes later it usually recovers. It's not clear to me yet what's causing the block. Restarting nfsd on the server will resolve the issue if it doesn't clear itself.
> 
> Any pointers for troubleshooting this? I've been looking through vmstat, gstat, top, etc. when the problem occurs, but I haven't been able to pinpoint the issue. I can get pcap, but it would be from the hosts, because I don't have a 10G tap or managed switch.
> 

run `nfsstat -d 1` and try to capture a few lines from before, during,
and after the stall, and that may provide some insight.

Specifically, does the queue length grow, suggesting it is waiting on
the I/O subsystem, or does it just stop getting traffic all together.


-- 
Allan Jude