Answer
Checkpoints flush memory pages to disk. On crash, MongoDB replays WAL only after the last checkpoint, reducing recovery time and ensuring durability.
Quick Answer
WiredTiger checkpoints every 60 seconds write a consistent data snapshot to disk. On crash, recovery starts from the last checkpoint and replays journal entries that occurred after. This bounds recovery time to journal entries from the last 60 seconds. If the journal is also lost (disk failure), recovery goes back to the prior checkpoint and loses up to 60 seconds of writes - hence use replica sets.
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