Cassandra Backup & Restore Procedure
Locations
o
commitlog_directory_location
Default out of the box location - /var/lib/cassandra/commitlog
o
data_directory_location
Default out of the box location - /var/lib/cassandra/data
Default out of the box location - /var/lib/cassandra/data
o
Snapshot location
<data_directory_location>/<keyspace_name>/<columnfamilyName> /snapshots/<snapshot_name>
Commands
o
Snapshot command (Basic)
nodetool snapshot
nodetool snapshot
o
Snapshot command (Advanced)
nodetool -h <host> -p <port> snapshot
[keyspaces...] -cf [columnfamilyName] -t [snapshotName]
o
Clearing Snapshot Files
(Basic)
nodetool clearsnapshot
o
Clearing Snapshot Files
(Advanced)
nodetool -h <host> -p <port> clearsnapshot
[keyspaces...] -t [snapshotName]
Backup procedure
o Setup Parameter
change incremental_backups to true in cassandra.yaml
stop
and start cassandra
o Backup
nodetool snapshot [keyspaces...] -cf [columnfamilyName] -t
[snapshotName]
Restore
To restore a node from a snapshot and incremental backups:
- Shut down the node to be
restored ( in cluster - shutdown all nodes ).
- Clear all files the in <commitlog_directory_location>.
- Clear all *.db files
in <keyspace_name>/<columnfamilyName>, but DO NOT delete the /snapshots and /backups subdirectories.
- If the restore is done to a new
server – make sure to create all keyspaces &
columnfamilyName directories the same as the
source.
- Locate the most recent snapshot
folder in <data_directory_location>/<keyspace_name>/<columnfamilyName>/snapshots/<snapshot_name>,
and copy its contents into <data_directory_location>/<keyspace_name>/<columnfamilyName>.
- If using incremental backups as
well, copy all contents of <data_directory_location>/<keyspace_name>/<columnfamilyName>/backups into
<data_directory_location>/<keyspace_name>/<columnfamilyName>.
- Restart the node (in cluster - startup
all nodes), keeping in mind that a
temporary burst of I/O activity will consume a large amount of CPU
resources.
- If the moved keyspace is new to the target host, you will need to write its information to the system keyspace (ie. Create the definition) this way:
On the source host:
Create a file called 'schema_export' and add the following lines inside:
use <keyspace_name>;
show schema;
then run this cassandra script and save the output in another file:
cassandra-cli –f schema_export > my.schema
Edit the file and remove non-command lines like "Connected to: "Test Cluster" on 127.0.0.1/9160".
On the target host:
cassandra-cli –f my.schema
