Consequence of lost ODB$ Files?

#1

Hi,

We use the Object DB backup utility for most of our backups, however we also do file system backups. Recently our file system backups have been failing because the .odb$ (write files) have been removed, by the DB Server, during the backup.  My question is that if we have a good back up of the associated .odb (main database file) and the .odb$ file is lost, will the main .odb file always be usable?  I do realize that any updates that were not transferred from the .odb$ file to the primary .odb file will be lost  (this is acceptable as this should always be a small amount of data).

Thank you,

Clinton Moore

#2

> if we have a good back up of the associated .odb (main database file) and the .odb$ file is lost, will the main .odb file always be usable?

Usually, but not always. If during the copy operation of the odb file to the backup it was changed by ObjectDB (e.g. new data was written to it) it is possible that your copy will be a corrupted database due to inconsistent file structure.

The online backup prevents that by delaying any changes to the database file until the copy is ended, so you have a snapshot of the database file with a valid structure. When you use file system copy of odb files while they are in use you don't have that protection.

If you already have database backup files that have been copied this way you should check their healthy with the ObjectDB Doctor, and if necessary, use the Doctor to repair any corrupted database files.

ObjectDB Support
ObjectDB - Fast Object Database for Java (JPA/JDO)

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