Oracle12c - EXPDP hangs when using NFS share

Question

I have a problem with the export via EXPDP for Oracle12 databases.

When the export is local, no problem. When I use an NFS share, the export starts, creates the log file, then nothing.

VM where the database is located: Oracle Linux Server - 6.10

Database version: Database Jan 2022 Release Update : 12.2.0.1.220118

VM where the NFS share is located: CentOS 7

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Export NFS:

/MY/PATH IP_DB_VM(rw,no_root_squash,sync)

FSTAB:

IP_NFS_VM:/MY/PATH /NFS_MOUNT_PATH nfs   rw,bg,hard,rsize=32768,wsize=32768,nfsvers=4,nointr,timeo=600,actimeo=0,tcp,nolock        0 0

I manage to mount the share, to write on it with the user oracle. But when I run the expdp utility, it hangs.

My expdp command:

expdp MY_USER@MY_DB full=y directory=MY_NFS_SHARE_DIRECTORY dumpfile=expdp_MYDB.dmp logfile=expdp_MYDB.log

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The export appears in DEFINING when I look at its state in the database, and I am then forced to kill the process (the KILL_JOB does not work)

If you have any idea what might be causing this behavior, and how to fix it!

Thanks in advance!

Answer 1

I managed to make the NFS mount work by changing the mount option nfsvers=4 to vers=4. I also deleted all jobs in NOT RUNNING and DEFINING state in case it could impact the other export/import jobs.

What remains unclear is that another NFS mount with the same configuration, and using the vers=4 option, still does not work.. I'll edit this answer if I find the cause for this 2nd problem

EDIT → I updated nfs packages on the other NFS VM, and reboot it. The expdp works now.