Michael Robinton > Mail-SpamCannibal > DATABASE

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DATABASE - RECOVERY

Nothing works!

It is possible to corrupt the Berkeley DB environment or one or more of the databases if a task is shutdown unexpectedly with the databases open.

The BerkeleyDB documentation says: www.sleepycat.com/docs/ref/transapp/app.html
  ...if any thread of control exits for any reason while holding Berkeley DB resources, recovery must be performed to do the following:
  • Recover the Berkeley DB resources.
  • Release any locks or mutexes that may have been held to avoid starvation as the remaining threads of control convoy behind the failed thread's locks.
  • Clean up any partially completed operations that may have left a database in an inconsistent or corrupted state.
Complicating this problem is the fact that the Berkeley DB library itself cannot determine whether recovery is required; the application itself must make that decision. A further complication is that recovery must be single-threaded; that is, one thread of control or process must perform recovery before any other thread of control or processes attempts to create or join the Berkeley DB environment.

If your SpamCannibal installation runs the sc_dbwatch daemon then database recovery is ordinarily done automatically. In the event things fail badly, you can check for a corrupted database by attempting to view one or more of the databases with sc_admin.pl. If you are running sc_BLcheck.pl periodically then the order of the databases by size is usually as shown below. If you can not view one or more of the databases then then the environment and/or the databases have been corrupted and the Berkeley DB db_recover program should be run.

To view:

  ./sc_admin archive view (small)
  ./sc_admin blcontrib view (large)
  ./sc_admin evidence view
  ./sc_admin tarpit view

Repairing the database

If the databases appear to be corrupted, you should be able to restore the database environment running the recovery procedure. Stop all SpamCannibal daemons that access the database then su - root and type:

  cd /usr/local/spamcannibal/scripts
  ./sc_initdb -R

If that does not work then use the manual procedure. Stop all SpamCannibal daemons that access the database and run db_recover.

  rc.sc_dbwatch stop
    or
  rc.dbtarpit stop
  rc.bdbaccess stop
  rc.dnsbls stop

  you must also block any Cron jobs

  cd /var/run/dbtarpit
  db_recover -v

If that still does not work then use the sc_recoverdb.pl script to verify/copy the records from the existing database files to new files, then replace the old files with the new. su - root and type FOR EACH DB FILE (typically tarpit, archive, blcontrib, evidence):

  cd /usr/local/spamcannibal/scripts
  ./sc_recoverdb.pl -v tarpit

If the DB fails to verify, then type:

  ./sc_recoverdb.pl tarpit
  cd /var/run/dbtarpit
  mv tarpit.new tarpit

Last resort recovery

Ok, so none of that worked either. As a last resort, you can dump a damaged database file using Berkeley DB's db_dump and the reload it with db_load.

See: The db_dump and db_load utilities on the Oracle / BerkeleyDB web site.

Reinitializing the database environment

To reinitialize the database environment su - root and type:

  cd /usr/local/spamcannibal/scripts
  ./sc_initdb.pl

Restart SpamCannibal daemons

Restart the SpamCannibal daemons that were previously running.

  rc.sc_dbwatch start
    or
  rc.dbtarpit start
  rc.sc_lbdaemon start
  rc.bdbaccess start
  rc.dnsbls start
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