nfs logging causes unstable system: kernel: xs_tcp_setup_socket: connect returned unhandled error -1

[Göran Törnqvist]

We hit an issue when a nfs server is unreachable and clients keep reconnecting to it causes syslog and kern.log files to be flooded with errors like:

kernel: xs_tcp_setup_socket: connect returned unhandled error -1

Approx 30.000 errors / second. This causes disk space to grow rapidly and fill the disk in a matter of minutes. Only solution appears to be to reboot the nfs servers.

Nfs server is running longhorn 1.5.3 and client mounts options look like:

... type nfs4 (rw,relatime,vers=4.1,rsize=1048576,wsize=1048576,namlen=255,softerr,softreval,noresvport,proto=tcp,timeo=600,retrans=5,sec=sys,clientaddr=10.125.92.24,local_lock=none,addr=10.43.81.150)

We did not experience this issue before longhorn introduced "soft" nfs options.
We have a SUSE/Longhorn support ticket (01053865) for this and they suggested us to report this here.

References/Possibly related to:
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy/commit/?h=Ubuntu-5.15.0-91.101&id=98f930fb6b46b128b72f5635925ec97f2f875d72

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# cat /proc/version_signature
Ubuntu 5.15.0-101.111-generic 5.15.143

# lsb_release -rd
Description: Ubuntu 22.04.4 LTS
Release: 22.04