gbak (1) - Linux Manuals

gbak: backup /restore Firebird database


gbak -- backup /restore Firebird database


gbak -b [backup option...] [common option...] source target

gbak -c|-r [restore option...] [common option...] source target


gbak is the tool for managing Firebird database logical backup and restore.

In backup mode source is the path to an existing database and target is the backup file name. If target is "stdout", the backup is sent to the standard output.

In restore mode source is an existing backup file and target is the path to a firebird database. If source is "stdin", the backup data is expected on the standard input.


Most options can be abbreviated. Below are given the shortest abbreviations as well as the full versions.
-user string
User name to use when connecting to the database.
-ro string
-role string
SQL role to use when connecting to theh database.
-pas string
-password string
Password to use when connecting to the database.
Use services manager when talking to the database.
Report each action.

Displays verbose information about what metadata is being processed, what table is being backed up/restored and how many records are processed.

-y string
Redirects status/error messages to the given path.
Prints full program version number before doing anything else. Prints server and database version information after connecting to the database.


Turns on backup mode.
Converts external tables into tables.

Normally external tables are ignored during backup and restore. With the -convert option external tables are included in the backup as any other regular table. When such a backup is restored, these previously external tables are created as regular tables.

-fa number
-factor number
Blocking factor. Output is written in block of number bytes. Useful when backing up to a tape.
Inhibits garbage collection.

Normally Firebird runs a garbage collector when reading through the tables. Since the backup process reads all the tables, this forces garbage collection of the whole database. Using this switch speeds up the backup process and also can help in some cases of backing up damaged databases.

Ignores records with bad checksums.

This option should be used only when backing up damaged databases.

Ignores transactions in limbo.
Backs up metadata only. No table content is included in the backup.
Uses non-transportable backup format.

Non-transportable backups can be restored only on machines using the same byte order.

Saves old-style metadata descriptions.


Turns on restore mode.

target database will be created and must not exist.

-r [o]
-recreate_database [overwrite]
Like -create_database, but by adding "overwrite" any existing database is overwritten.
Turns on restore mode. Target database is overwritten if it exists.
-bu number
-buffers number
When creating target database, ignore information about database buffers stored in the backup and use specified number.
Normally, Firebird uses RLE compression for strings when storing them on disk. This option turns this compression off.
Restore indexes in inactive state. This can be used to restore a backup, containing data inconsistent with foreign key/unique constraints.

Note that since version 3.0 gbak leaves any problematic indices in inactive state automatically.

Does not restore database shadow files.
-mo access
-mode access
Restores the database with given access.

Valid values for access are "read_only" and "read_write". The default is to restore the database with its original access mode.

Restores the database without its validity constraints. This includes foreign key, unique and check constraints. Useful for restoring a backup, containing inconsistent data.
Commits restoring transaction after each table.
-p number
-page_size number
Override page size stored in the backup. Valid values are 1024, 2048, 4096, 8192, 16384 and 32768.
Normally, Fireburd reserves some space on each data page for further use. This reserved space is used for newly inserted data and for keeping older versions of the data. Having space reserved for this purpose ``near'' to the data speeds up modifications. If the database will be used mainly for read operations, specifying this option will save disk space.
-fix_fss_metadata string
When restoring metadata, in case it is not valid UTF8, try to convert it from the specified character set. Useful when table descriptions are given in some national non-UTF8 encoding, which was possible with Firebird before version 2.5.
-fix_fss_data string
When restoring table data, in case a column defined with UNICODE_FSS character set contains no valid UTF8 (which was possible with versions of Firebird prior to 2.5), try to convert the data from the specified character set.


When the target argument is in the form file_1 pages_1 ... file_N, the restored database is written in several files with file_i not bigger than pages_i pages. This may be useful if the file system that holds the database file can't handle files above certain size.

Note 1: the file size limit is in pages.

Note 1: there is no limit on the size of the last file.


Default value for the -user option.
Default value for the -role option.
Default value for the -password option.


Backup a database into a compressed format

gbak -b srv:/database.fdb stdout | gzip > database.fbk.gz

Restore a database from a compressed backup

zcat database.fbk.gz | gbak -c stdin srv:/new-database.fdb


This manual page was written by Damyan Ivanov dmn [at] for the Debian project. Permission is granted to use this document, with or without modifications, provided that this notice is retained. If we meet some day, and you think this stuff is worth it, you can buy me a beer in return.


isql-fb(1), gfix(1), fbstat(1).

Additional documentation about Firebird can be found on the Firebird Project website, <>.