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Configuring file system replication

This option has been replaced by a new filter driver. You may be instructed to use this legacy driver by technical support.

In order to use Double-Take Availability replication, data that will be replicated must reside on a partition, which is specially mounted with the Double-Take Availability file system (DTFS) driver. DTFS is a transparent file system that monitors the storage file system so that data changes can be captured. Data on the file system can only be replicated if it is under DTFS mount points.

DTSetup allows you to configure entries in /etc/DT/dtfs_mounts to mount specific partitions as DTFS when Double-Take Availability is started.

When making replication configuration changes, stop any applications that may be running and restart them after the replication changes have been made. Double-Take Availability needs to be loaded on the file system before any applications, otherwise some data may not be replicated.

When protecting an NFS or Samba server, Double-Take Availability should be mounted just above the local file system where the exported NFS or Samba data resides. Additionally, NFS and/or Samba must be started after the Double-Take daemon.

DTFS mounts should remain mounted for the duration of the system uptime, if possible. Any file handles that a process has open on a DTFS mount location before DTFS is mounted will not be captured by replication. Since DTFS mounts are not automatically unmounted when the Double-Take daemon is stopped, the command service DTMount stop can be used to stop all DTFS mounts, if necessary.

1. Start DTSetup.
2. Select Setup tasks.
3. Select Configure File System or Block Device Replication.
4. Select (DEPRECATED) Configure File System Replication setup file.
5. To add a DTFS mount, select Add an entry to /etc/DT/dtfs_mounts.

6. Specify the path of the highest subdirectory for which replication should be captured. This can be the path to a mount point or a subdirectory of a volume.

   Do not select the root as a replication mount point.

   If you have a single drive system, mount DTFS to any of the subdirectories directly under root.

    

7. You will be prompted whether you want to replicate access times. The access-time file property changes during a mirror and causes replication operations to be generated during a mirror and every time a file is read from or written to. This may have a negative effect on performance. If you do not replicate access times on both the source and target when the volume is initially mounted, you may increase the performance, especially during mirroring. (Access times from files closes are always replicated regardless of this configuration.) Specify yes or no to replicate access times.
8. To remove any DTFS mounts, select Remove /Umount entries in /etc/DT/dtfs_mounts and specify the path that you want to remove.
9. To immediately mount all of the entries in /etc/DT/dtfs_mounts, select Mount all entries in /etc/DT/dtfs_mounts as DTFS. If you do not select this option, you must stop and restart the daemon for the changes to take effect.

10. To immediately unmount all of the entries in /etc/DT/dtfs_mounts, select Unmount DTFS from all entries in /etc/DT/dtfs_mounts. This allows you to make changes to DTFS mounts without unloading the daemon.

    If you are using Konqueror, you can only unmount a replication mount point by rebooting the server.

     

11. When you have completed your file system replication configuration, press Q as many times as needed to return back to the main menu or to exit DTSetup.

You can also mount and unmount DTFS manually using the Setup Tasks, Configure File System or Block Device Replication, (DEPRECATED) Manual Replication Configuration menu option. Changes made from this menu are not persisted between reboots/restarts.