Crash recovery in JDataStore

By: Ben Matterson

Abstract: How JDatStore recovers from failures, including media failures.

How does JDataStore support Crash Recovery?

Crash recovery is automatic. The system should automatically recover from all failures except media failures when it is reopened.

Since JDataStore is as a low administration embeddable database, it is mostly focussed on automatic recovery of the more common failures like:

  • abnormal application termination
  • operating system crash
  • power failure
Recovery from damaged media can be accomplished, but requires more administration.

A media failure in the database file itself (*.jds) may be recovered if:
  1. There is a backup copy of the .jds file.
  2. All the log files that were created since the last .jds file backup were archived.

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