Answer
WiredTiger writes operations to WAL before flushing data pages. After crashes, MongoDB replays the WAL to restore data, ensuring strong durability guarantees.
Quick Answer
WiredTiger writes every change to the journal (write-ahead log) before applying it to data files. Each journal entry records the operation fully. On crash, MongoDB opens from the last checkpoint (data snapshot) and replays all journal entries that came after. This guarantees durability - a committed, journaled write is never lost even in sudden power failure.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ