man gbak (Commandes) - Backup/restore Firebird database
NAME
gbak - Backup/restore Firebird database
SYNOPSIS
gbak -b [backup option ...] [common option ...] source target
gbak -c|-r [restore option ...] [common option ...] source target
DESCRIPTION
gbak is the tool for managing Firebird database backup and restore.
In backup mode source is an existing database path (may include server name) and target is backup file name. It could be also a special device name like /dev/stdout (to redirect backup data to STDOUT) or /dev/st to put the backup on tape.
In restore mode source is existing backup file (or special device like /dev/stdin for STDIN or /dev/st to get the backup from tape) and target is path to firebird database and may include server name.
All options can be abbreviated. Below both full versions of options and the shortest possible versions are given.
COMMON OPTIONS
-user username
User name to use when connecting to database. Overrides environment variable. See ENVIRONMENT.
-ro[le] role_name
SQL role to use when connecting to database. Overrides environment variable. See ENVIRONMENT.
-pas[sword] password
Password to use when connecting to database. Overrides environment variable. See ENVIRONMENT.
-se[rvice]
Use service manager when talking to a database.
-v[erify]
Report each action.
Displays verbose information about what metadata is being processed, what table is being backed up/restores and how many records are processed.
-y path
Redirect status/error messages to the given path.
-z
Report full version number before doing anything else.
BACKUP OPTIONS
-b[ackup_database]
Turn on backup mode.
-co[nvert]
Convert external tables into tables.
Normally external tables are ignored during backup and restore. With -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[ctor]
FIXME
-g[arbage_collect]
Inhibit 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. In case you make the backup just to restore it over the existing database this garbage collection is unnecessary. Another reason to use this options is if a garbage collection is engaged by other means - either by using gfix or the automatic sweep. Using this switch speeds up the backup process and also can help in some cases of backing up damaged databases.
-ig[nore]
Ignore records with bad checksums.
This option should be used only when backing up damaged databases.
-l[imbo]
Ignore transactions in limbo.
This switch causes the backup process to ignore transactions in limbo state.
-m[etadata_only]
Backup metadata only.
With this option only the metadata is written to the backup. This includes all tables/views/triggers/indexes/stored procedures/domains/generators etc. No table data is included in backup. Such a backup is useful for creating an "empty" copy of a database.
-nt
Use non-transportable backup format.
By default a "transportable" backup format is used. This means you can backup a database on little-endian machine and restore it on big-endian machine and vice versa. By using -nt the backup is only usefull on machines with the same "endianness".
-ol[d_descriptions]
FIXME
RESTORE OPTIONS
-c[reate_database]
Turn on restore mode.
target database will be created and must not already exist.
-r[eplace_database]
Turn on restore mode.
If target exists it is overwritten.
-bu[ffers] num
When creating target database, ignore information about database buffers stored in the backup and use specified number of buffers.
-e[xpand]
Normally, Firebird uses RLE compression for strings when storing them on disk. This option turns this compression off.
-i[nactive]
Restore indexes in inactive state. This can be used to restore a backup, containing data inconsistent with foreign key/unique constraints.
-k[ill]
Do not create shadows when restoring.
Normally and database shadows are created during restore. This option inhibits this.
-mo[de] access
Restore database with given access.
Valid values for access are read_only and read_write. Default is to restore the database with its original access mode.
-n[o_validity]
Restore database without its validity constraints. This includes foreign key, unique and check constraints. Usefull for restoring a backup, containing inconsistent data.
-o[ne_at_a_time]
Commit restoring transaction after restoring each table.
-p[age_size] num
Override page size stored in the backup. Valid values for num are 1024, 2048, 4086, 8192, 16384 and 32768.
-use_[all_space]
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 used mainly for read operations specifying -use_all_space will save some space. This option is partocularly useful when restoring a read-only database, since read-only databases do not need any additional space for back-versions.
RESTORING TO MULTIPLE-FILE DATABASE
Previously, Firebird was not able to work with 64-bit file pointers thus limiting databases to (about) 2GB of size per database.
Since 2GB is not much of data frome years, there is a mechanism for spreading the database into multiple files. This way you can have multiple 2GB files, containing all your data.
When restoring to multiple-file database the target argument is of form: file_1 pages_1 file_2 pages_2 ... file_N-1 pages_N-1 file_N
Each pages_n specifies at most how many pages to put in file_n. Last in the list is a filename without page limit - it will contain all the pages not fit in file_N-1. Note that pages_n is measured in pages, not bytes so the numbers depend on page size.
Imagine you have a filesystem (or an ancient OS) which only supports 32-bit file pointers. To play safe, you decide to split your database on 2GB files. If the page size for the database is 8192, then each file can have up to 2*1024*1024*1024/8192 = 262144 pages.
NOTE
Note that on a recent OS and filesystem Firebird can use 64-bit file pointers rendering multi-file databases unnecessary.
ENVIRONMENT
As all other Firebird utilities, gbak accepts followint environment variables:
- ISC_USER
- default value for -user option
- ISC_ROLE
- default value for -role option
- ISC_PASSWORD
- default value for -password option
EXAMPLES
In all examples -user, -role and -password options are omited for clarity. In a real world situation they (or their corresponding enviromnemt variables) should be used.
Note that filename extensions used here are just recommended. Using unified extensions scheme helps guess file type just by looking at its extension.
Here are some commonly used extensions:
- .fdb
- Firebird database
- .gdb
- Firebird database, legacy extension from the days when Firebird was Interbase. gdb actually comes from Grotton database, named after the company that created the software back in ??? FIXME
- .fdb.2
- Second file of multi-file database
- .fdb.3
- Third file of multi-file database
- .fdb.N
- N-th file of multi-file database
- .fbk
- Firebird backup file
- .gbk
- Legacy extension for backup file
- .fbk.gz
- Gzipped backup file
Backup a database into a compressed format:
gbak -b db-srv://database.fdb /dev/stdout | gzip > /file.fbk.gz
Restore a database into new filename:
zcat /file.fbk.gz | gbak -c /dev/stdin db-srv://new-database.fdb
AUTHOR
This manpage was written by Damyan Ivanov <divanov@creditreform.bg> for Debian GNU/Linux but may be used by others.
COPYRIGHT
Permission is granted to modify and distribute this manpage under the terms of GNU General Public Licence version 2 or (at your oppinion) any later version. It is provided in the hope that it will be useful but with NO WARRANTY. Author is not responsible for any (mis)use of this manpage.