Use this command to increase space for the database by
adding directories for the database to use.
Privilege class
To issue this command, you
must have system privilege or unrestricted storage privilege.
When you issue the EXTEND DBSPACE command,
directories are added to the database. With the default parameter
settings, data is redistributed across all database directories, and
storage space is reclaimed. This action improves parallel I/O performance
and makes the new directory space available for immediate use.
If
you do not want to redistribute data when you add new directories,
you can specify RECLAIMSTORAGE=NO. If you specify No for
this parameter, all space in existing directories is filled before
new directories are used. You can redistribute data and reclaim space
later, but you must complete the manual procedure for this task by
using DB2 commands.
Restriction: Redistribution of data and reclaiming of space as part of an operation to
extend database space works only with DB2 Version 9.7 or later table spaces. The table spaces
are created when you format a new Tivoli® Storage
Manager
Version 6.2 or later server. If you upgraded or restored your Tivoli Storage
Manager server from V6.1, you cannot redistribute data
or reclaim space. You must issue the EXTEND DBSPACE command with
RECLAIMSTORAGE=NO.
Important: The redistribution process uses
considerable system resources, so ensure that you plan ahead when
you want to add space to the database. Review the following guidelines:
- Complete the process when the server is not handling a heavy workload.
- The time that is required to redistribute data and reclaim space might vary. It is affected by
factors such as the file system layout, the ratio of new paths to existing storage paths,
server hardware, and concurrent operations. To get a rough estimate, you can try the operation
with a small Tivoli Storage
Manager database on a lab
system. Use your results as a reference to estimate the time that is required for the
procedure.
- Do not interrupt the redistribution process. If you try to stop
it, for example, by halting the process that is completing the work,
you must stop and restart the DB2® server.
When the server is restarted, it will go into crash recovery mode,
which takes several minutes, after which the redistribution process
resumes.
When you add directories
to the database, ensure that you follow best practices. For more information,
see Configuring the server database directories for optimal
performance.
After an operation to extend the database space is complete, halt and restart the server to fully
use the new directories. If the existing database directories are nearly full when a new
directory is added, the server might encounter an out of space condition (reported in the
db2diag.log). You can fix the out of space condition by halting and
restarting the server.
Syntax
.-,------------.
V |
>>-EXTend DBSpace----db_directory-+----------------------------->
.-REClaimstorage--=--Yes-----. .-Wait--=--No------.
>--+----------------------------+--+------------------+--------><
'-REClaimstorage--=--+-No--+-' '-Wait--=--+-No--+-'
'-Yes-' '-Yes-'
Parameters
- db_directory (Required)
- Specifies the directories for database storage. The directories
must be empty and accessible by the user ID of the database manager.
A directory name must be a fully qualified name and cannot exceed
175 characters in length. Enclose the name in quotation marks if it
contains embedded blanks, an equal sign, or other special characters.
If you are specifying a list of directories for database storage,
the maximum length of the list can be 1400 characters.
Restriction: You cannot specify Universal
Naming Convention (UNC) paths.
- REClaimstorage
- Specifies whether data is redistributed across newly created database directories and space is
reclaimed from the old storage paths. This parameter is optional. The default value is Yes.
Unless you specify WAIT=YES, the operation is completed as a
background process.
- Yes
- Specifies that data is redistributed so that new directories are available for immediate
use.
Important: The redistribution process uses considerable system resources
so ensure that you plan ahead.
After the process starts, messages are issued to
inform you about the progress. You can use the QUERY PROCESS command to
monitor the operation. To cancel the process, you can use the CANCEL
PROCESS command, but if a data redistribution operation is in progress, it
completes before the process is stopped.
- No
- Specifies that data is not redistributed across database directories and storage space
is not reclaimed when space is added for the database.
- Wait
- Specifies whether this command is processed in the background
or foreground.
- No
- Specifies background processing. The default is NO.
- Yes
- Specifies foreground processing.
You
cannot specify YES from the server console.
Example: Add directories
to the storage space for the database, redistribute data, and reclaim
storage
Add two directories (
/tsm_db/stg1 and
tsm_db/stg2)
under the
/tsm_db directory to the storage space
for the database. Issue the command:
extend dbspace /tsm_db/stg1,/tsm_db/stg2
Example: Add drives to the storage
space for the database, redistribute data, and reclaim storage
Add
drives D and E to the storage space for the database. Issue the command:
extend dbspace D:,E:
Related commands
Table 1. Commands
related to EXTEND DBSPACECommand |
Description |
DSMSERV EXTEND DBSPACE |
Adds directories to increase space for
use by the database. |
QUERY DB |
Displays allocation information about the database. |
QUERY DBSPACE |
Displays information about the storage space
defined for the database. |