How do I back-up KahaDB
In creating a backup, there may be an issue with the lock file, or with an inuse journal file. The lock file is not important but you would want the latest journal files.
- Freeze the filesystem containing the database to ensure that you get a consistent snapshot of the journal.
- Back-up the database using any of the standard back-up mechanisms.
Batch writes are serialised and followed by an fsync, so the fsfreeze will either block the next write or the next fsync. Either way is fine from a consistency point of view. The index is checkpointed to the journal periodically, so recovery of the index will at worst be from the last know good state.