Forcibly Unmounting NFS Filesystems

forcibly unmounting nfs filesystems

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Figure 3 - Setup a “surrogate” NFS server (part 2)

The following steps were used in the above example to simulate an NFS filesystem hang

scenario and then to create a “surrogate” NFS server:

1. The bdf(1M) command shows the mounted NFS filesystems.

2. The dd(1) command is used to generate file I/O in the target NFS filesystem. In

this example, the dd(1) command is writing to a file in the NFS filesystem.

3. At this point, the NFS server crashes and the dd(1) command hangs.

4. Because the dd(1) command did not complete and has outstanding I/O requests

requiring a response from the server, the NFS filesystem is considered busy and

cannot be unmounted.

5. The fuser(1M) command is used to identify any processes with files open in the

target filesystem. In this example, fuser(1M) reports that no processes have files

open in the specified NFS filesystem.