apache/cassandra · error · RuntimeException

Unable to resolve canonical path for

Error message

Unable to resolve canonical path for 

What it means

CompactionInfo.targetDirectory converts the compaction's target directory to a canonical path; if FileOps.canonicalPath throws for any reason, the Throwable is replaced by this RuntimeException (note the original cause is not chained and the message ends with the path).

Source

Thrown at src/java/org/apache/cassandra/db/compaction/CompactionInfo.java:187

            ColumnFamilyStore cfs = ColumnFamilyStore.getIfExists(metadata.id);
            if (cfs != null)
                return cfs.getDirectoriesForFiles(sstables);
        }
        return Collections.emptyList();
    }

    public String targetDirectory()
    {
        if (targetDirectory == null)
            return "";

        try
        {
            return new File(targetDirectory).canonicalPath();
        }
        catch (Throwable t)
        {
            throw new RuntimeException("Unable to resolve canonical path for " + targetDirectory);
        }
    }

    /**
     * Note that this estimate is based on the amount of data we have left to read - it assumes input
     * size == output size for a compaction, which is not really true, but should most often provide a worst case
     * remaining write size. We also scale by the effective compression ratio since total/completed are for the uncompressed size.
     */
    public long estimatedRemainingWriteToDiskBytes()
    {
        if (unit == Unit.BYTES && tasktype.writesData)
        {
            final long total = getTotal();
            double compressionRatio = total == 0 ? 1 : ((double) totalCompressed / (double)total);
            return (long)(compressionRatio * (total - getCompleted()));
        }
        return 0;
    }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Verify the data directory exists and is mounted; restart the node if the filesystem recovered.
2. Check node logs for the original Throwable preceding this message to find the root cause.
3. Repair or re-create the damaged data directory and run a scrub/rebuild if needed.

File dir = new File(targetDirectory);
if (!dir.exists() || !dir.isDirectory()) throw new IllegalStateException("target directory missing: " + targetDirectory);

try { String canonical = info.getTargetDirectory(); } catch (RuntimeException e) { if (e.getMessage().startsWith("Unable to resolve canonical path")) { checkMountsAndLogs(); } }

When it happens

Trigger: Computing the target directory of an in-progress compaction (e.g. via compactionstats/JMX) when the underlying filesystem call fails — path no longer exists, I/O error, or permission problem on the directory.

Common situations: Data directory removed/moved while compaction was running, NFS/mount issues, disk detached from the instance.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• Failed importing SSTables
• Throwing new Runtime to bypass exception handler when disk i
• FSReadError
• FSWriteError
• FSWriteError

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/7c7727c276177968. Report an issue: GitHub.