Reconfiguring an NFS v4 mount from read-only to read-write

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Hello --

We are running Red Hat Enterprise Linux 7.4 on one of our servers. The server is also running the nfs v3 client to mount a filesystem that is exported from an Oracle SunOS server. This latter system utilizes the nfs v4 daemon.

The entry in the /etc/fstab file of the Red Hat server that mounts the exported filesystem is the following:

:/ /oraclearchive nfs sec=sys suid,dev,exec 0 0

This configuration allows read access. I would like to change the configuration to read/write access. I believe the correct syntax to use is the following:

:/ /oraclearchive nfs sec=sys suid,dev,exec,rw 0 0

My questions are the following:

  1. Is my proposed syntax correct?
  2. Can I make the change in question, run the umount command on the mount in question, and then run mount -a aftewards?


HI Andrew,

  1. The syntax looks good.
  2. the umount and mount look good.

One point to check, is the export on the server side rw too?

If not that needs to be fixed or the file system will still be read-only.


Jan Gerrit Kootstra

Hello Jan --

Thank-you for the feedback. I checked the /etc/dfs/dfstab on the remote system, and I confirmed the system in question has read/write access.

I was able to make the changes in question, and I ran a test copy of a directory to the mount. The problem that I am now seeing is the following error message:

cp: cannot create directory ‘//’: Input/output error

The directory gets created, but there are no contents. The source system is running the nfsclient v3 as opposed to the destination system running the nfs 4 server. Could the discrepancy between the two cause this problem?

Hello Jan -- This is a follow-up to my previous posting. There are several other servers running either an earlier version of Red Hat Enterprise Linux, or Ubuntu 16.04. LTS, and both have the nfs v4 client. When attempting the same operation on those systems, the cp command completed without issue.