NFS issues since upgrading to 13-RELEASE

Juraj Lutter otis at
Thu Apr 15 21:09:38 UTC 2021

> On 15 Apr 2021, at 22:47, Rick Macklem <rmacklem at> wrote:
> Allan Jude wrote:
>> 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.
> otis@ has run into a problem that sounds similar.
> He sees a growing Recv-Q size on the server for the TCP connection from the client
> when "netstat -a" is done on the server when the "hang" occurs.
> In his case, he is using a Linux client and it does not recover, however other client
> mounts continue to function.


> I suspect the recovery after a few minutes is the client establishing a new TCP
> connection.
> He has been running for almost a week with r367492 reverted and has not reported
> seeing the problem again (he had reported that it has taken up to a week to recur, so
> reverting r367492 *might* have fixed the problem and I'd guess we'll know in another
> week?).

We are now running 4 days without interruption. Before r367492 was reverted, it was
unpredictable when it will lock up. The best result we achieved was 7 days.

The machine it’s running on is definitely a slow or weak one (it’s dell r740xd with 2x CPU, 256GB RAM, 22xNVMe data zpool).


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