Cluster Node Operations
- Former user (Deleted)
1. Log in to the WSO2 Storage Server management console and select "Cassandra Tools ->Â Cassandra Operations" sub menu in the "Main" menu.
2. The "Cluster Nodes" window opens. Click on one "View Operations" link associated with each cluster node in the cluster.
3. The "Node Operations" window opens. It contains all the cluster-node-level, keyspace -level and column-family-level operations such as backup, flush, scrub, shutting down RPC and Gossip servers etc.
Let's take a look at each of these operations in detail.
- General Cassandra Operations
- Backup Operations
- Server Operations
- Cache Operations
- Other Operations
- Keyspace Operations
General Cassandra Operations
Decommission
Decommission operation removes the node from the cluster. If there is only one node in the cluster, it cannot be removed and an error message will be shown.
Drain
Drain operation flushed the entire node. This causes the node to stop accepting write request until it is restarted.
Move
Move operation changes node's currant token to a new one. This is important when load-balancing a cluster.
Perform GC
Perform GC (Garbage Collector) operation activates garbage collector on the node. This operation affects the overall latency of the node's activities.
Backup Operations
Take Snapshot
Enables the user to backup data in the node.
Clear Snapshot
Enables to clear backups taken by "Take Snapshot" operation and free memory utilized for them.
Enable Incremental Backup
Allows to fully backup data in a node and also continue to write data to an existing backup as and when additional data comes to the node after a backup is taken.
Server Operations
Stop RPC
Allows to shutdown and restart the RPC server of the node.
Stop Gossip
Allows to shutdown and restart the Gossip server of the node.
Cache Operations
Invalidate Row Cache
Set Cache Capacity
Other Operations
Remove Token
Allows to remove a token in the cluster or force-remove completion operations listed under this operation. User gets a live update of the currant token removal status in the management console.
Stop Compaction
Allows to stop any listed permitted compaction under this operation.
Rebuild
Allows to specify an available data center for rebuild.
Set Stream Throughput
Allows to set the stream throughput of the node.
Set Compaction Throughput
Allows to set the compaction throughput for the node.
Keyspace Operations
4. Click the "Keyspace Operations" link at the bottom of the "Node Operations" window.
5. The "Keyspace Operations" window opens with a list of operations is associated with each keyspace as follows.
Let's take a look at each of these operations in detail.
Repair
Compares replica for each key responsible for the node and all replicas are updated to the newest available version.
Compact
Triggers major compaction in all column families in the keyspace and performs compaction of multiple SS tables into a single SS table.
Flush
Flushes memtables (in memory) to SSTables (on disk), which also enables CommitLog segments to be deleted.
Cleanup
Triggers Cassandra to cleanup keys which do not further belong to the node.
Scrub
Scrub operation rebuilds sstables with correct bloom filters, with no data loss. The nodetool scrub creates a snapshot of data files before rebuilding.
UpgradeSSTables
While the Scrub operation rebuilds your sstables, it also discards data it deems broken and creates a snapshot of it, which has to be removed manually. To rebuild your sstables without going through this process, it is best to use UpgradeSSTables operation, which is particularly useful when upgrading your server or changing compression options.
Take Snapshot
Backs-up the keyspace data.
Clear snapshot
Clears the backup of a keyspace.