Remote file system I/O fails with the “Function not implemented” error message when UID mapping is enabled

There are error messages when remote file system has an I/O failure and the course of action that you can take to correct this issue.

When user ID (UID) mapping in a multi-cluster environment is enabled, certain kinds of mapping infrastructure configuration problems might result in I/O requests on a remote file system failing:
ls -l /fs1/testfile
ls: /fs1/testfile: Function not implemented
To troubleshoot this error, verify the following configuration details:
  1. That /var/mmfs/etc/mmuid2name and /var/mmfs/etc/mmname2uid helper scripts are present and executable on all nodes in the local cluster and on all quorum nodes in the file system home cluster, along with any data files needed by the helper scripts.
  2. That UID mapping is enabled in both local cluster and remote file system home cluster configuration by issuing the mmlsconfig enableUIDremap command.
  3. That UID mapping helper scripts are working correctly.

For more information about configuring UID mapping, see the IBM® white paper UID Mapping for GPFS in a Multi-cluster Environment (https://www.ibm.com/docs/en/storage-scale?topic=STXKQY/uid_gpfs.pdf).