Creates a backup copy of a database or a table
space.
For information about the backup operations supported
by DB2® database systems between
different operating systems and hardware platforms, see "Backup
and restore operations between different operating systems and hardware
platforms".
Scope
In a partitioned database environment,
if no database partitions are specified, this command affects only
the database partition on which it is executed.
If the option
to perform a partitioned backup is specified, the command can be called
only on the catalog database partition. If the option specifies that
all database partition servers are to be backed up, it affects all
database partition servers that are listed in the db2nodes.cfg file.
Otherwise, it affects the database partition servers that are specified
on the command.
Authorization
One of the following authorities:
Required connection
Database. This command
automatically establishes an exclusive connection to the specified
database.
Note: If a connection to the specified database already
exists, that connection will be terminated and a new connection established
specifically for the backup operation. The connection is terminated
at the completion of the backup operation.
Command
syntax
>>-BACKUP--+-DATABASE-+--database-alias------------------------->
'-DB-------'
>--+-------------------------------------+---------------------->
'-USER--username--+-----------------+-'
'-USING--password-'
>--+---------------------------------------------------------------------------------------+-->
'-ON--+-+-DBPARTITIONNUM--+--| Partition number(s) |----------------------------------+-'
| '-DBPARTITIONNUMS-' |
'-ALL DBPARTITIONNUMS--+------------------------------------------------------+-'
'-EXCEPT--+-DBPARTITIONNUM--+--| Partition number(s) |-'
'-DBPARTITIONNUMS-'
>--+---------------------------------------+--+--------+-------->
| .-,---------------. | '-ONLINE-'
| V | |
'-TABLESPACE--(----tablespace-name-+--)-'
>--+------------------------+----------------------------------->
'-INCREMENTAL--+-------+-'
'-DELTA-'
>--+-----------------------------------------------------------+-->
+-USE--+-+-TSM--+-| Open sessions |----------+--| Options |-+
| | '-XBSA-' | |
| '-SNAPSHOT--+-----------------------+-' |
| +-LIBRARY--library-name-+ |
| '-SCRIPT--script-name---' |
+-LOAD--library-name--| Open sessions |--| Options |--------+
| .-,-------. |
| V | |
'-TO----+-dir-+-+-------------------------------------------'
'-dev-'
>--+--------------+--+----------------------------+------------->
'-DEDUP_DEVICE-' '-WITH--num-buffers--BUFFERS-'
>--+---------------------+--+----------------+------------------>
'-BUFFER--buffer-size-' '-PARALLELISM--n-'
>--+------------------------------------------------------------------+-->
'-COMPRESS--+----------------+--+---------+--+-------------------+-'
'-COMPRLIB--name-' '-EXCLUDE-' '-COMPROPTS -string-'
>--+------------------------------------+--+--------------+----->
'-UTIL_IMPACT_PRIORITY--+----------+-' +-EXCLUDE LOGS-+
'-priority-' '-INCLUDE LOGS-'
>--+-------------------+---------------------------------------><
'-WITHOUT PROMPTING-'
Partition number(s)
.-,--------------------------------------------------.
V |
|--(----db-partition-number1--+--------------------------+-+--)--|
'-TO--db-partition-number2-'
Open sessions
|--+------------------------------+-----------------------------|
'-OPEN--num-sessions--SESSIONS-'
Options
|--+-------------------------------+----------------------------|
'-OPTIONS--+-"options-string"-+-'
'-@--file-name-----'
Command parameters
- DATABASE | DB database-alias
- Specifies the alias of the database to back up.
- USER username
- Identifies the user name under which to back up the database.
- USING password
- The password used to authenticate the user name. If the password
is omitted, the user is prompted to enter it.
- ON
- Backup the database on a set of database partitions.
- DBPARTITIONNUM db-partition-number1
- Specifies a database partition number in the database partition
list.
- DBPARTITIONNUMS db-partition-number1 TO db-partition-number2
- Specifies a range of database partition numbers, so that all partitions
from db-partition-number1 up to and including db-partition-number2 are
included in the database partition list.
- ALL DBPARTITIONNUMS
- Specifies that the database is to be backed up on all partitions
specified in the db2nodes.cfg file.
- EXCEPT
- Specifies that the database is to be backed up on all partitions
specified in the db2nodes.cfg file, except those
specified in the database partition list.
- DBPARTITIONNUM db-partition-number1
- Specifies a database partition number in the database partition
list.
- DBPARTITIONNUMS db-partition-number1 TO db-partition-number2
- Specifies a range of database partition numbers, so that all partitions
from db-partition-number1 up to and including db-partition-number2 are
included in the database partition list.
- TABLESPACE tablespace-name
- A list of names used to specify the table spaces to be backed
up.
- ONLINE
Specifies
online backup. The default is offline backup. Online backups are only
available for databases configured with logarchmeth1 enabled.
During an online backup, DB2 obtains
IN (Intent None) locks on all tables existing in SMS table spaces
as they are processed. S (share locks) are no longer held on LOB
data in SMS table spaces during online backup.
- INCREMENTAL
- Specifies a cumulative (incremental) backup image. An incremental
backup image is a copy of all database data that has changed since
the most recent successful, full backup operation.
- DELTA
- Specifies a noncumulative (delta) backup image. A delta backup
image is a copy of all database data that has changed since the most
recent successful backup operation of any type.
- USE
- TSM
- Specifies that the backup is to use Tivoli® Storage Manager (TSM)
as the target device.
- XBSA
- Specifies that the XBSA interface is to be used. Backup Services
APIs (XBSA) are an open application programming interface for applications
or facilities needing data storage management for backup or archiving
purposes.
- SNAPSHOT
- Specifies that a snapshot backup is to be taken.
You cannot
use the
SNAPSHOT parameter with any of the following
parameters:
- TABLESPACE
- INCREMENTAL
- WITH num-buffers BUFFERS
- BUFFER
- PARALLELISM
- COMPRESS
- UTIL_IMPACT_PRIORITY
- SESSIONS
The default behavior for a snapshot backup is a full database
offline backup of all paths that make up the database including all
containers, local volume directory, database path (DBPATH),
and primary log and mirror log paths (INCLUDE LOGS is
the default for all snapshot backups unless EXCLUDE LOGS is
explicitly stated).
- LIBRARY library-name
- Integrated into IBM® DB2
Server is a DB2 ACS API driver
for the following storage hardware:
- IBM TotalStorage SAN Volume
Controller
- IBM Enterprise Storage Server® Model
800
- IBM Storwize® V7000
- IBM System Storage® DS6000™
- IBM System Storage DS8000®
- IBM System Storage N Series
- IBM XIV®
If you have other storage hardware, and a DB2 ACS API driver for that storage hardware,
you can use the LIBRARY parameter to specify
the DB2 ACS API driver.
The value of the LIBRARY parameter is a
fully-qualified library file name.
- SCRIPT script-name
- The name of the executable script capable of performing a snapshot
backup operation. The script name must be a fully qualified file name.
- OPTIONS
-
- "options-string"
- Specifies options to be used for the backup operation.
The string will be passed exactly as it was entered, without the double
quotation marks.
- @ file-name
- Specifies that the options to be used for the backup operation
are contained in a file located on the DB2 server.
The string will be passed to the vendor support library. The file
must be a fully qualified file name.
You cannot use the vendoropt database
configuration parameter to specify vendor-specific options for snapshot
backup operations. You must use the OPTIONS parameter
of the backup utilities instead.
- OPEN num-sessions SESSIONS
- The number of I/O sessions to create between the DB2 product and the TSM product or another backup
vendor product. This parameter has no effect when you back up to tape,
disk, or other local device. If you specify the INCLUDE
LOGS parameter for an online backup, an extra session is
created for the OPEN num-sessions SESSIONS parameter
after the initial sessions are closed. If you are creating a Single
System View (SSV) online backup, for each node backed up, an extra
session is created for the OPEN num-sessions SESSIONS parameter
after the initial sessions are closed. If you use this parameter with
the TSM option, the number of entries that are created
in the history file is equal to the number of sessions created.
- TO dir | dev
A
list of directory or tape device names. The full path on which the
directory resides must be specified. If USE
TSM, TO, and LOAD are
omitted, the default target directory for the backup image is the
current working directory of the client computer. This target
directory or device must be locally addressable on the database server.
In
a partitioned database, the target directory or device must exist
on all database partitions, and can optionally be a shared path.
The directory or device name may be specified using a database partition
expression. For more information about database partition expressions,
see "Automatic storage databases".
This parameter can be
repeated to specify the target directories and devices that the backup
image will span. If more than one target is specified (target1, target2,
and target3, for example), target1 will be opened first. The media
header and special files (including the configuration file, table
space table, and history file) are placed in target1. All remaining
targets are opened, and are then used in parallel during the backup
operation. Because there is no general tape support on Windows operating systems, each type of tape
device requires a unique device driver.
Use of tape devices or floppy disks might generate
messages and prompts for user input. Valid response options are:
- c
- Continue. Continue using the device that generated the warning
message (for example, when a new tape has been mounted)
- d
- Device terminate. Stop using only the device that generated
the warning message (for example, when there are no more tapes)
- t
- Terminate. Abort the backup operation.
If the tape system does not support the ability
to uniquely reference a backup image, it is recommended that multiple
backup copies of the same database not be kept on the same tape.
- LOAD library-name
- The name of the shared library (DLL on Windows operating systems) containing the
vendor backup and restore I/O functions to be used. It can contain
the full path. If the full path is not given, it will default to the
path on which the user exit program resides.
- DEDUP_DEVICE
- Optimizes the format of the backup images for target storage devices
that support data deduplication.
- WITH num-buffers BUFFERS
- The number
of buffers to be used. If the number of buffers that you specify is
not enough to create a successful backup, then the minimum value necessary
to complete the backup is automatically chosen for this parameter.
If you are backing up to multiple locations, you can specify a larger
number of buffers to improve performance. If you specify the COMPRESS parameter,
to help improve performance, you can add an extra buffer for each
table space that you specify for the PARALLELISM parameter.
- BUFFER buffer-size
- The size, in 4 KB pages, of the buffer used when building the
backup image. DB2 will automatically
choose an optimal value for this parameter unless you explicitly enter
a value. The minimum value for this parameter is 8 pages.
If using
tape with variable block size, reduce the buffer size to within the
range that the tape device supports. Otherwise, the backup operation
might succeed, but the resulting image might not be recoverable.
With
most versions of Linux, using
the default buffer size included with DB2 for
backup operations to a SCSI tape device results in error SQL2025N,
reason code 75. To prevent the overflow of Linux internal SCSI buffers, use this formula:
bufferpages <= ST_MAX_BUFFERS * ST_BUFFER_BLOCKS / 4
where
bufferpages is
the value you want to use with the
BUFFER parameter,
and
ST_MAX_BUFFERS and
ST_BUFFER_BLOCKS are
defined in the Linux kernel
under the
drivers/scsi directory.
- PARALLELISM n
- Determines the number of table spaces which can be read in parallel
by the backup utility. DB2 will
automatically choose an optimal value for this parameter unless you
explicitly enter a value.
- UTIL_IMPACT_PRIORITY priority
- Specifies that the backup will run in throttled mode, with the
priority specified. Throttling allows you to regulate the performance
impact of the backup operation. Priority can be any number between 1 and 100,
with 1 representing the lowest priority, and 100 representing
the highest priority. If the UTIL_IMPACT_PRIORITY keyword
is specified with no priority, the backup will run with the default
priority of 50. If UTIL_IMPACT_PRIORITY is
not specified, the backup will run in unthrottled mode. An impact
policy must be defined by setting the util_impact_lim configuration
parameter for a backup to run in throttled mode.
- COMPRESS
- Indicates that the backup is to be compressed.
- COMPRLIB|ENCRLIB
name
- Indicates the name of the library that is used during the compression process. For
example, db2compr.dll for Windows; libdb2compr.so for Linux and UNIX operating systems. The name must be a fully qualified path
that refers to a file on the server. If this parameter is not specified, the default DB2 compression
library is used. If the specified library cannot be loaded, the backup fails.
- EXCLUDE
- Indicates that the compression library is not stored in the backup image.
- COMPROPTS|ENCROPTS
string
- Describes a block of binary data that is passed to the initialization routine in the
library. DB2 passes this string directly from the client to the server. Any issues of byte reversal
or code page conversion is handled by the compression library. If the first character of the data
block is '@', the remainder of the data is interpreted by DB2 as the name of a file found on the
server. DB2 then replaces the contents of string with the contents of this file and passes this new
value to the initialization routine. The maximum length for string is 1024 bytes.
- EXCLUDE LOGS
- Specifies that the backup image should not include any log files.
When performing an offline backup operation, logs are excluded whether
or not this option is specified, with the exception of snapshot backups.Logs
are excluded by default in the following backup scenarios:
- Offline backup of a single-partitioned database.
- Online or offline backup of a multi-partitioned database, when
not using a single system view backup.
If you specify EXCLUDE
LOGS with a snapshot backup, log files can be written to
during the backup. These log files are included by default in the
snapshot backup, but are not usable for recovery. If this backup is
restored, the log files must not be extracted from the backup. If
the log path was set to the default when the backup was taken, then
it is not possible to exclude the log files from being restored and
they must be deleted manually after the backup is restored. If the
log path was not the default, then the log files can be excluded at
restore time by using the LOGTARGET EXCLUDE options
with the RESTORE DATABASE command.
- INCLUDE LOGS
- Specifies that the backup image should include the range of log
files required to restore and roll forward this image to some consistent
point in time. This option is not valid for an offline backup, with
the exception of snapshot backups. INCLUDE LOGS is
always the default option for any online backup operation, except
a multi-partitioned online backup where each database partition is
backed up independently (that is, a non-single system view backup).
If any of the log files that are required for the
backup have previously been backed up and are no longer in the log
path, then the DB2 database
manager retrieves them for backup from the overflow log path, if the
path has been set. Otherwise, the database manager retrieves them
for backup from the current log path or mirror log path. These log
files are removed from the log path after the backup has completed.
- WITHOUT PROMPTING
-
Specifies that the backup will run unattended,
and that any actions which normally require user intervention will
return an error message.
Note: - If the backup command indicates which partitions in a partitioned
database are to be backed up, the backup operation is implicitly performed WITHOUT
PROMPTING.
- Options that are specified on the BACKUP DATABASE command
in a partitioned database environment will be applied on each partition
individually. For example, if a backup operation is specified to USE
TSM OPEN 3 SESSIONS, DB2 will
open three TSM sessions on each partition.
Examples
- In the following example, the database WSDB is defined on all
4 database partitions, numbered 0 through 3. The path /dev3/backup is
accessible from all database partitions. Database partition 0 is
the catalog partition. To perform an offline backup of all the WSDB
database partitions to /dev3/backup, issue the
following command from database partition 0:
db2 BACKUP DATABASE wsdb ON ALL DBPARTITIONNUMS TO /dev3/backup
The
backup is performed simultaneously on all partitions. All four database
partition backup images will be stored in the /dev3/backup directory,
which can be a shared directory accessible from more than one partition,
or a locally-mounted directory accessible from each partition individually,
or a combination of both.
- In the following example database SAMPLE is backed up to a TSM
server using two concurrent TSM client sessions. DB2 calculates the optimal buffer size for this
environment.
db2 backup database sample use tsm open 2 sessions with 4 buffers
- In the following example, a table space-level backup of table
spaces (syscatspace, userspace1) of database payroll is
done to tapes.
db2 backup database payroll tablespace (syscatspace, userspace1) to
/dev/rmt0, /dev/rmt1 with 8 buffers without prompting
- The USE TSM OPTIONS keywords can be used
to specify the TSM information to use for the backup operation. The
following example shows how to use the USE TSM OPTIONS keywords
to specify a fully qualified file name:
db2 backup db sample use TSM options @/u/dmcinnis/myoptions.txt
The
file myoptions.txt contains the following information: -fromnode=bar
-fromowner=dmcinnis
- Following is a sample weekly incremental backup strategy for a
recoverable database. It includes a weekly full database backup operation,
a daily noncumulative (delta) backup operation, and a midweek cumulative
(incremental) backup operation:
(Sun) db2 backup db sample use tsm
(Mon) db2 backup db sample online incremental delta use tsm
(Tue) db2 backup db sample online incremental delta use tsm
(Wed) db2 backup db sample online incremental use tsm
(Thu) db2 backup db sample online incremental delta use tsm
(Fri) db2 backup db sample online incremental delta use tsm
(Sat) db2 backup db sample online incremental use tsm
- In the following example, three identical target directories are
specified for a backup operation on database SAMPLE. You might want
to do this if the target file system is made up of multiple physical
disks.
db2 backup database sample to /dev3/backup, /dev3/backup, /dev3/backup
The
data will be concurrently backed up to the three target directories,
and three backup images will be generated with extensions .001, .002,
and .003.
- In the following example, the database WSDB is defined on all
4 database partitions, numbered 0 through 3. Database partition 0
is the catalog partition. To perform an online backup of table space
USERSPACE1 on database partitions 1 and 2, with the backup image to
be stored on a TSM server, issue the following command from partition
0:
db2 BACKUP DATABASE wsdb ON DBPARTITIONNUMS (1, 2) TABLESPACE (USERSPACE1)
ONLINE USE TSM
- Sample output generated to indicate the sqlcode returned
by each partition.
- Example 1
- All partitions are successful (sqlcode >= 0)
$ db2 backup db foo on all dbpartitionnums tablespace(T1)
Part Result
---- ------
0000 DB20000I The BACKUP DATABASE command completed successfully.
0001 SQL2430W The database backup succeeded, but the following
table spaces do not exist on this database partition: "T1".
Backup successful. The timestamp for this backup image is :
20040908010203
- Example 2
- One or more partitions fail (sqlcode < 0)
$ db2 backup db foo on all dbpartitionnums to /backups
Part Result
---- ------
0000 SQL2001N The utility was interrupted. The output data may be incomplete.
0001 SQL2419N The target disk "/backups" has become full.
SQL2429N The database backup failed. The following database partitions returned errors: "1".
- The following backups will include the log directories in the
image created:
db2 backup db sample use snapshot
db2 backup db sample online use snapshot
db2 backup db sample use snapshot INCLUDE LOGS
db2 backup db sample online use snapshot INCLUDE LOGS
- The following backups will NOT include the log directories in
the image created:
db2 backup db sample use snapshot EXCLUDE LOGS
db2 backup db sample online use snapshot EXCLUDE LOGS
Usage notes
- The data in a backup cannot be protected by the database server.
Make sure that backups are properly safeguarded, particularly if the
backup contains LBAC-protected data.
- When backing up to tape, use of a variable block size is currently
not supported. If you must use this option, ensure that you have well
tested procedures in place that enable you to recover successfully,
using backup images that were created with a variable block size.
- The
backup utility cannot be used with a Type 2 connection.
- When using a variable block size, you must specify a backup buffer
size that is less than or equal to the maximum limit for the tape
devices that you are using. For optimal performance, the buffer size
must be equal to the maximum block size limit of the device being
used.
- Snapshot backups should be complemented with regular disk backups
in case of failure in the filer/storage system.
- As you regularly backup your database, you might accumulate very
large database backup images, many database logs and load copy images,
all of which might be taking up a large amount of disk space. Refer
to "Managing recovery objects" for information about how to manage
these recovery objects.
- You can use the OPTIONS parameter
to enable backup operations in TSM environments supporting proxy nodes.
For more information, see the "Configuring a Tivoli Storage Manager client" topic.
- You
can use the DB2_BCKP_PAGE_VERIFICATION registry
variable to enable DMS and AS page validation during the backup.
- You can use the DB2_BCKP_INCLUDE_LOGS_WARNING registry
variable to specify that some online backups can now succeed even
if they have not successfully included all of the required logs.
- After
you issue a BACKUP DATABASE command with the ONLINE option
and the INCLUDE LOGS option, the resulting backed-up
database image includes all the log files necessary to roll forward
to the end of backup.