You can use various commands to back up and restore a directory
server instance. Based on your requirements, you must choose the appropriate
command to back up and restore a directory server.
There are several ways to back up and restore a directory server
instance, each with its own set of advantages and disadvantages.
- idsdbback and idsdbrestore
- The idsdbback and idsdbrestore commands
are provided by IBM® Security Directory
Server
to back up a directory server instance. When you back up, both DB2® database
and directory server configuration files are backed up. The advantages
of using these commands are in backing up and restoring of the directory
server configuration. To know more about these commands, see IBM Security Directory
Server Command
Reference.
- The other backup options that are provided with IBM Security Directory
Server do
not include the directory server configuration information. The directory
server configuration information includes directory schema, configuration
file, and key stash file. Although, it is possible to back up these
files manually; the idsdbback and idsdbrestore commands
make this task easier.
- The disadvantage of using the idsdbback and idsdbrestore commands
is less flexibility in how the underlying DB2 restore
is done. For example, with the idsdbrestore command,
the DB2 restore
cannot be directed to distribute the database across multiple disks.
- db2lif, ldif2db, and bulkload
- The db2ldif and ldif2db commands
are provided by IBM Security Directory
Server to
export data from a database to a Lightweight Directory Interchange
Format (LDIF) file. You can also use the commands to import the data
into the database from the LDIF file. The advantage to using these
commands is the portability, standardization, and size factors that
they provide.
- The output LDIF file can be used to restore a directory server
on a different operating system. Because the LDIF
format is text-based, it is relatively easy to modify an LDIF file.
- The disk space that is required for an LDIF file with entries
is considerably less than the space required for a DB2 backup
with the entries. The disk
space requirement for the LDIF output from db2ldif is
approximately six times less than the backed up database from db2
backup or idsdbback. The disadvantage
with db2ldif and ldif2db is
the time that is required to complete the process, which is more when
compared to db2 backup and db2 restore.
- For restoring the database, the bulkload command
is many times faster than the ldif2db command,
but is still much slower than db2 restore.
It is because the db2 backup and db2 restore commands
are essentially a disk copy, and they are the fastest alternative.
- Unlike db2 restore, to restore a directory
server by using bulkload, the directory server
must be empty. It can be accomplished by restoring an empty database,
or by unconfiguring, and then reconfiguring the directory server.
It is not advisable to drop the database and re-create it using DB2 commands.
Creating the database manually misses some important configuration
steps that are part of Configuration Tool.
- db2 backup and
db2 restore
- The db2 backup and db2 restore commands
are provided by DB2.
The advantage of using these commands is the performance and flexibility
in specifying the location of the database files. The db2
restore command can be used to distribute the database across
multiple disks or to move the database to another directory. For more
information, see Distributing
the database across multiple physical disks.
- A disadvantage of the db2 backup and db2
restore commands are their complexity. Another disadvantage
is the potential incompatibility in backing up and restoring across
operating systems and across DB2 versions.
For more information, see the appropriate DB2 backup
and restore documentation.
- An important consideration when you use the db2 backup and db2
restore commands is the preservation of DB2 configuration
parameters and system statistics optimizations in the backed-up database.
The restored database has the same performance optimizations as the
backed-up database. When you use the LDAP commands db2ldif, ldif2db,
or bulkload, the performance optimization might
not be restored.
- If you restore over an existing database, any performance optimization
on that existing database is lost. Check all DB2 configuration
parameters after you restore the directory server instance. If you
do not know whether db2 runstats was run before
the database was backed up, tune the DB2 system
statistics after the restore (see Update
the DB2 system
statistics). Use the following DB2 commands
to run backup and restore operations:
db2 force applications all
db2 backup db ldapdb2 to directory_or_device
db2 restore db ldapdb2 from directory_or_device replace existing
Where, directory_or_device is
the name of a directory or device where the backup is stored.
- One of the most common errors that occurs during a restore operation
is a file permission error. The error might occur due to the following
reasons: