apache/hadoop · error · IOException

Mount table {mountTableName} has already been configured wit

Error message

Mount table {mountTableName} has already been configured with regular links. A merge slash link should not be configured.

What it means

Error "Mount table {mountTableName} has already been configured with regular links. A merge slash link should not be configured." thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/InodeTree.java:705

        // ignore - we set home dir from config
        continue;
      } else {
        throw new IOException("ViewFs: Cannot initialize: Invalid entry in " +
            "Mount table in config: " + src);
      }

      final String target = si.getValue();
      if (linkType != LinkType.MERGE_SLASH) {
        if (isMergeSlashConfigured) {
          throw new IOException("Mount table " + mountTableName
              + " has already been configured with a merge slash link. "
              + "A regular link should not be added.");
        }
        linkEntries.add(
            new LinkEntry(src, target, linkType, settings, ugi, config));
      } else {
        if (!linkEntries.isEmpty()) {
          throw new IOException("Mount table " + mountTableName
              + " has already been configured with regular links. "
              + "A merge slash link should not be configured.");
        }
        if (isMergeSlashConfigured) {
          throw new IOException("Mount table " + mountTableName
              + " has already been configured with a merge slash link. "
              + "Multiple merge slash links for the same mount table is "
              + "not allowed.");
        }
        isMergeSlashConfigured = true;
        mergeSlashTarget = target;
      }
    } // End of for loop.

    if (isMergeSlashConfigured) {
      Preconditions.checkNotNull(mergeSlashTarget);
      root = new INodeLink<T>(mountTableName, ugi,
          initAndGetTargetFs(), mergeSlashTarget);

View on GitHub (pinned to 2add963021)

Solutions

1. Do not configure a merge slash link for a mount table that already has regular links.
2. Replace the regular links with linkMergeSlash, or drop the merge slash entry.

When it happens

Trigger: Thrown during ViewFs mount table initialization when a merge-slash link is configured for a mount table that already has regular links; the two link types cannot be mixed.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/174e9695e616f37a. Report an issue: GitHub.