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CHAPTER 11 Backup and Data Recovery

When you back up the files and restore them with the CATALOG ONLY option, you don’t see anything telling you that these files were links; in fact, this information is not saved.

Adaptive Server IQ saves these files as though they were actually present in the directory where the symbolic links reside. When you do the restore, the files are recreated in the directories or on the raw partitions named by the database name. Whether or not the links exist at restore time, they will never be used again. The database is restored to its original location.

Unattended backup

With the ATTENDED OFF option, you can specify that no operator will be present during a backup. Adaptive Server IQ currently supports two unattended backup features:

•The operator does not need to respond to prompts during the backup.

•The archive devices can be stacker drives, which automatically load a set of tapes into a single drive. You can use stacker drives for both attended and unattended backups.

Unattended backup tries to detect all possible reasons for a backup failing except tape media failure, and report any potential errors before attempting the backup, such as available space on disk or tape, and consistent size and block factor.

For unattended backup to disk, Adaptive Server IQ first tests whether there is enough free disk space for the backup, However, it does not preallocate the backup files to reserve the space. If another user writes to that disk and as a result there is not enough room for the backup, the backup fails when disk space runs out.

For backup to tape, you must estimate how much data each tape will hold, and specify that number of kilobytes in the TO archive_device parameter of the BACKUP command. The backup program checks information stored internally to see how much room it needs to back up your database. If it determines that there is enough room on the tape, the backup proceeds. However, if you overestimate the amount of space available on the tape(s) and the backup runs out of space, the backup fails at that point.

If you omit the SIZE parameter for an unattended backup, the entire backup must fit on one tape.

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