Backing Up a File System
This procedure optionally uses the frozen mode feature. Frozen mode enables you to stop database updates on disk so that a file system snapshot can be taken safely. You can use frozen mode as an additional measure for ensuring a robust backup.
If the server instance is stopped, frozen mode does not apply.
Your server must not write user data on the disk while the file system backup is in progress. If you are sure that no updates will occur during a certain time frame, make your backup during this time. If you cannot guarantee that there will be no updates, put your server into frozen mode before making a backup.
A server in frozen mode continues to write to the access and errors logs. In a single-server topology, operations received when frozen mode is on result in an LDAP error being returned. The error message logged is the standard error for the database being offline. In a replicated topology, a referral is returned. For frozen mode to work correctly, no other tasks should be running on the databases.
Note that the databases of a server in frozen mode are more stable than those in read-only mode. Unlike frozen mode, read-only mode permits tasks to be created and configuration entries to be modified. When frozen mode is on, all configured databases are taken offline. Any internal operations in progress are notified of the database going offline. LDAP operations in progress are completed, and the database environment is flushed. Subsequent incoming operations, including searches to user data, are refused until frozen mode is set to off. You can, however, search configuration parameters while frozen mode is on.
Frozen mode can be active only when the server is running. Restarting the server instance will also reset frozen mode to off.
To Back Up a File System
For parts of this procedure, you can use DSCC to perform this task. For information, see Directory Service Control Center Interface and the DSCC online help. Other parts of the procedure can only be done using the command line.
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(Optional) Put your server into frozen mode.
$ dsconf set-server-prop -h host -p port read-write-mode:frozen
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Back up your file system, using a tool appropriate to your file system type.
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If your server is in frozen mode, make the server read-write again.
$ dsconf set-server-prop -h host -p port read-write-mode:read-write
If your server receives replication updates from another server, replication updates will start as soon as frozen mode is turned off.
To Restore the File System
For parts of this procedure, you can use DSCC to perform this task. For information, see Directory Service Control Center Interface and the DSCC online help. Other parts of the procedure can only be done using the command line.
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