I have found the root cause, in my test environment the clients are all clones with unique machine-id but the same hostname. The issue is resolve by either changing the hostname of each client, or by setting a unique value here:
echo options nfs nfs4_unique_id=[string] > /etc/modprobe.d/nfsclient.conf In my production environment the clients all share the same NFS root, and I'm not sure how to set a random value in nfsclient.conf (I tried nfs4_unique_id=`cat /proc/sys/kernel/random/uuid` but this doesn't work). Currently I can work around by setting a random hostname. If anyone can suggest how to do this via nfsclient.conf instead that might be neater. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1960826 Title: NFSv4 performance problem with newer kernels To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1960826/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs