Creates a client-side or a server-side backup of database files and transaction logs for running databases.
dbbackup [ options ] target-directory| Option | Description | ||
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| @data |
Reads in options from the specified environment variable or configuration file. See Using configuration files. If you want to protect passwords or other information in the configuration file, you can use the File Hiding utility to obfuscate the contents of the configuration file. See File Hiding utility (dbfhide). |
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| -b block-size | Specifies the maximum block size (in number of pages) to be used to transfer pages from the database server to dbbackup. The dbbackup utility tries to allocate this number of pages; if it fails, it repeatedly reduces this value by half until the allocation succeeds. The default size is 128 pages. | ||
| -c "keyword=value; ..." |
Specifies connection parameters. The user ID must have DBA authority or REMOTE DBA authority to connect to the database. See Connection parameters. For example, the following command backs up the sample database running on the database server sample_server, connecting as the DBA user, into the SQLAnybackup directory:
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| -d | Backs up the main database files only, without backing up the transaction log file, if one exists. | ||
| -k checkpoint-log-copy-option |
Specifies how dbbackup processes the database files before writing them to the destination directory. The choice of whether to apply pre-images during a backup, or copy the checkpoint log as part of the backup, has performance implications. If the -s option is specified to perform the backup on the server, the default setting for -k is auto; otherwise, the default setting is copy. auto The database server checks the amount of available disk space on the volume hosting the backup directory. If there is at least twice as much disk space available as the size of the database at the start of the backup, then the backup proceeds as if copy was specified. Otherwise, it proceeds as if nocopy was specified. This setting can only be used if -s is also specified. copy The backup reads the database files without applying pre-images for any modified pages. The checkpoint log in its entirety and the system dbspace, are copied to the backup directory. The next time the database is started, the database server automatically recovers the database to its state as of the checkpoint at the start of the backup. Because page pre-images do not have to be written to the temporary file, using this option can provide better backup performance and reduce internal server contention for other connections that are operating during a backup. However, since the backup copy of the database file includes the checkpoint log, which has pre-images of any pages modified since the start of the backup, the backed-up copy of the database files may be larger than the database files at the time the backup started. The copy option should be used when disk space in the destination directory is not an issue. nocopy The checkpoint log is not copied as part of the backup. This option causes pre-images of modified pages to be saved in the temporary file so that they can be applied to the backup as it progresses. The backup copies of the database files will be the same size as the database when the backup operation commenced. The backup copies may actually be slightly smaller because the checkpoint log is not present in this copy. This option results in smaller backed up database files, but the backup may proceed more slowly, and possibly decrease performance of other operations in the database server. It is useful in situations where space on the destination drive is limited. recover The database server copies the checkpoint log (as with the copy option), but applies the checkpoint log to the database when the backup is complete. This restores the backed up database files to the same state (and size) that they were in at the start of the backup operation. This option is useful if space on the backup drive is limited (it requires the same amount of space as the copy option for backing up the checkpoint log, but the resulting file size is smaller). This setting can only be used if -s is also specified. |
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| -l filename |
Enables a secondary system to be brought up rapidly in the event of a server crash. A live backup does not stop. It continues running while the server runs. It runs until the primary server becomes unavailable. At that point, it shuts down, but the backed up log file is intact and can be used to bring a secondary system up quickly. See Differences between live backups and transaction log mirrors and Make a live backup. If you specify -l, then you cannot use -s to create an image back up on the server. |
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| -n |
Changes the naming convention of the backup transaction log file to yymmddxx.log, where xx are sequential letters ranging from AA to ZZ and yymmdd represents the current year, month, and day. This option is used in conjunction with -r. The backup copy of the transaction log file is stored in the directory specified in the command, and with the yymmddxx.log naming convention. This allows backups of multiple versions of the transaction log file to be kept in the same backup directory. You can also use both the -x option and the -n option to rename the log copy. For example
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| -o filename | Writes output messages to the named file. | ||
| -q | Does not display output messages. This option is available only when you run this utility from a command prompt. | ||
| -r |
Renames the transaction log and starts a new transaction log. It forces a checkpoint and causes the following three steps to occur:
Do not use this option if you are using database mirroring. See Database mirroring and transaction log files. |
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| -s | Creates an image backup on the server using the BACKUP DATABASE statement. If you specify the -s option, the -l option (to create a live backup of the transaction log) cannot be used. The directory specified is relative to the server's current directory, so it is recommended that you specify a full pathname. In addition, the server must have write permissions on the specified directory. When -s is specified, the Backup utility does not display progress messages and does not prompt you when it overwrites existing files. If you want to be prompted when an attempt is made to overwrite an existing file, do not specify -s or -y. You must specify -s if you specify the -k recovery option. | ||
| -t | Creates a backup that can be used as an incremental backup since the transaction log can be applied to the most recently backed up copy of the database file(s). | ||
| -x | Backs up the existing transaction log, deletes the original log, and then starts a new transaction log. Do not use this option
if you are using database mirroring. See Database mirroring and transaction log files.
CautionUsing this option can result in a database that cannot be recovered from media failure. You should only use this option when data loss is acceptable. |
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| -xo | Deletes the current transaction log and starts a new one. This operation does not perform a backup; its purpose is to free up disk space in non-replication environments. Do not use this option if you are using database mirroring. See Database mirroring and transaction log files. | ||
| -y | Creates the backup directory or replaces a previous backup file in the directory without confirmation. If you want to be prompted when an attempt is made to overwrite an existing file, do not specify -s or -y. | ||
| target-directory | Specifies the directory the backup files are copied to. If the directory does not exist, it is created. However, the parent directory must exist. By default, the Backup utility creates a client-side backup of the database files. You can specify -s to create a backup on the server using the BACKUP DATABASE statement. |
The Backup utility makes a backup copy of all the files for a single database. A simple database consists of two files: the main database file and the transaction log. More complicated databases can store tables in multiple files, with each file as a separate dbspace. All backup file names are the same as the database file names. The image backup created by the Backup utility consists of a separate file for each file that is backed up.
For more information about making archive backups (a single file that contains both the database file and the transaction log), see Archive backups.
Using the Backup utility on a running database is equivalent to copying the database files when the database is not running. You can use the Backup utility to back up the database while other applications or users are using it.
If neither of the options -d or -t are used, all database files are backed up.
By default, the Backup utility creates a client-side backup of the database files. You can specify -s to create a backup on the server using the BACKUP DATABASE statement.
For information about performing server-side backups, see BACKUP statement.
Backup copies of the database and transaction log must not be changed in any way. If there were no transactions in progress during the backup, or if you specified BACKUP DATABASE WITH CHECKPOINT LOG RECOVER or WITH CHECKPOINT LOG NO COPY, you can check the validity of the backup database using read-only mode or by validating a copy of the backup database.
However, if transactions were in progress, or if you specified BACKUP DATABASE WITH CHECKPOINT LOG COPY, the database server must perform recovery on the database when you start it. Recovery modifies the backup copy, which is not desirable.
In addition to dbbackup, you can access the Backup utility in the following ways:
From Sybase Central, using the Create Backup Images Wizard. See Image backups.
From Interactive SQL, using the BACKUP DATABASE statement. See BACKUP statement.
For more information about recommended backup procedures, see Backup and data recovery.
Exit codes are 0 (success) or non-zero (failure).
For more information about exit codes, see Software component exit codes.
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