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This one is a bit weird.

We have a closed network of about five (5) Red Hat Workstation 7 assets in one of our development laboratories. One of the REHL 7 machines is hosting a USB connected DroboPro via NFS to the other machines - the other machines are mounting this share on boot via /etc/fstab. Everything works great and all users and access the share - unless the machine hosting the NFS share goes down. When that machine is shut down or brought offline, the share is inaccessible (obviously), but the other machines also experience a side effect we can't explain.

If the machine hosting the share is off, and we lock the screen or reboot any of the other four (4) RHEL 7 machines, they lockup/freeze and are inaccessible until the machine hosting the NFS share is brought back online.

We've narrowed the source down to the NFS share by unmounting it on the other four (4) RHEL 7 assets and bringing down the share, which resulted in no locking/freezing.

/etc/exports > /dir/path/ 192.168.100.0/24(rw)

Any insight or recommendation for further troubleshooting would be appreciated.

Thanks.

2 Answers2

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give this a try: add the following flags to your nfs mount point in /etc/fstab:

bg,intr,soft,timeo=3,retrans=3,actimeo=3,retry=3

adjust timeout rates accordingly but i found this combination works the best. Ensure "default" is not set in nfs mount point line and read the man pages for nfs to see exactly how this would effect your mount point.

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Quick and maybe dirty solution from the top of my head:

  • check regularly if NFS - Server is available
  • If NFS Server is unavailable, lazy-unmount the NFS shares on the client

This could be as simple as:

while true;
do
  ping -c 1 $NFSserver || umount -l $NFSmounts
done

Of course you would have to think about building a list with the $NFSmounts if you have more than one.

Depending on the scheduling of the job, this would unlock the workstations really quick as soon as they have unmounted the unavailable NFS mounts.

Rel: Preventing broken NFS connection from freezing the client system

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