MongoDB recovery planning
MongoDB's WiredTiger engine uses checkpoints and a journal to recover from ordinary interruptions. Disk-level corruption, missing files, damaged metadata, or inconsistent copies can prevent automatic recovery and make repair lossy.
Understand the symptom
WiredTiger checkpoints provide consistent on-disk recovery points, while journal records cover more recent operations. Copying selected collection files or deleting lock, journal, or metadata files can break that relationship. MongoDB documents repair for cases where disk corruption prevents startup, but repair can discard unrecoverable content and must be tested on protected copies.
What you may see
WiredTiger cannot open metadata, replay recovery, or read required table files.
Storage pages or metadata fail validation and the engine protects itself from further work.
A partial copy, cleanup, filesystem fault, or failed storage may have removed a required component.
The engine cannot reach a usable checkpoint with the available journal and data files.
Protect the source
Repair aims for a usable database and may remove records or tables it cannot reconstruct.
Journal files may contain changes newer than the last durable checkpoint.
Collection, index, metadata, journal, and encryption files must represent the same storage state.
Do this now
Prevent automatic restarts, writes, replica actions, and backup agents from changing dbPath.
Preserve every WiredTiger file, collection, index, journal, diagnostic, lock, and configuration file.
Record MongoDB and FCV versions, standalone or replica role, storage engine, encryption, and recent maintenance.
Acquire failing volumes before repair, resync, filesystem checks, or repeated startup attempts.
NEPFOSYS process
NEPFOSYS correlates metadata, checkpoints, journal, tables, indexes, logs, version, and physical storage.
Startup, repair, salvage, or replica-assisted paths are tested without changing the source.
Recovered databases, collections, documents, indexes, and date ranges are checked against priorities.
A clear next step
Start a case with the exact symptoms, incident timeline, prior attempts, encryption details, and the files that matter most. NEPFOSYS will route the case to the appropriate DFW intake or nationwide mail-in path.
Start with a case reviewQuestions, answered
It normally recovers from the last valid checkpoint plus journal, but disk corruption or missing files can prevent automatic recovery.
No. It changes the database and can discard content that cannot be repaired. Use a protected copy and validate the result.
Keep the entire dbPath, journal, WiredTiger metadata and history store, collection and index files, configuration, logs, keys, and storage snapshot.
DFW local · Nationwide mail-in