What does this ERROR mean

The SSTableTidier process did not find a file as expected when performing post-compaction cleanup.

Why does this ERROR occur?

The Cassandra compaction process reads existing source SSTables and rewrites them to new SSTables. After the new SSTables are written, there is a cleanup process ( SSTableTidier) which validates which source SSTables should be deleted. SSTableTidier specifically checks for the source SSTables' *Data.db file(s) before deletion . If any of the source *Data.db file(s) is/are not found, the error is logged and SSTableTidier continues its cleanup process by deleting the associated source SSTable files.

There are two possibilities where source SSTables are removed prior to SSTableTidier being run:

• Manual Intervention: files were manually deleted or moved from the directory.
• Race Condition: files were deleted by the cleanup process prior to SSTableTidier completing its validation. This typically occurs on nodes installed on a Windows OS.

How do you fix this ERROR?

No remediation steps are necessary since the source SSTable files will be deleted anyway. If the error persists, please contact Datastax Support.