Moving the Cassandra database to a different disk drive
In some cases, the Cassandra database may need to be moved to a different disk drive.
This is especially the case if Cassandra is hosted on the same machine as DataMiner. To ensure optimal performance, the database should be located on a different drive than DataMiner. If your Cassandra database is currently on the same drive, you should move it to a different disk drive.
To do so:
Stop the DMA.
Note
To reduce the size of the data that will need to be copied, at this point, it can be useful to first do a cleanup of the snapshots that are used in Cassandra, by means of the Cassandra nodetool. For Windows, nodetool is located by default in the folder C:\Program Files\Cassandra\bin\. For Linux, the tool is available system-wide by default.
- To check the size of the snapshots, run the following command in a command prompt window: nodetool listsnapshots.
- To clean up the snapshots, run the following command in a command prompt window: nodetool clearsnapshot. This will mark all snapshots as ready for deletion. Then restart the Cassandra service in order to remove the snapshots.
Stop the Cassandra service
Locate the file cassandra.yaml. By default, it is located in the folder /etc/cassandra on Linux and C:\Program Files\Cassandra\conf on Windows.
Open the .yaml file (as Administrator) and look for the attribute data_file_directories.
Edit this attribute so that it points to the new disk you wish to use.
Locate the current Cassandra data directory. By default, this is /var/lib/cassandra/data on Linux and C:\ProgramData\Cassandra on Windows.
Copy the data from this directory to the new data directory you wish to use.
Note
- Depending on the size of the database, copying the existing database may take a while.
- Do not place the Cassandra database on a network attached storage (NAS) device or in a shared network file system (NFS). Such a setup is not supported by Cassandra.
When the copy is complete, start the Cassandra service.
Start the DMA.