Managing decision data nodes
For each decision data node that is listed on the Services landing page, you can perform certain actions, depending on the service.
- In the header of Dev Studio, click .
-
Click one of the following tabs to access the service whose nodes you want to
manage.
- Decision Data Store
- Adaptive Decision Manager
- Data Flow
- Visual Business Director
- Stream
-
For the selected node, expand the Execute menu and select one of
the available actions. Available actions include:
- Start – Activates the decision data node. The status of that node changes to NORMAL.
- Stop – Deactivates the decision data node. The status of that node changes to STOPPED.
-
Repair – Removes inconsistencies across all replicas of the
data sets in a decision data node. Run this operation in the following cases:
- As part of node recovery, when bringing a node back into the cluster after a failure.
- As part of the maintenance of nodes containing data that is not frequently read.
- As part of the update process of nodes that were offline.
-
Compact – Invokes the process in which the Cassandra database
combines multiple physical data files on the file system to improve the performance of
partition scans and to reclaim space from deleted data. Compaction is a background
operation that runs on a regular basis across all nodes in the decision data node
cluster, but you can run it explicitly on one decision data node by using the Compact
action. CAUTION:
The compaction operation causes a temporary spike in disk usage and disk I/O. Do not run this operation during peak usage hours on multiple decision data nodes concurrently, because it affects performance for any process or request accessing the decision data node storage.
-
Clean up – Removes keys that no longer belong to the decision
data node. Keys do not belong to a decision data node if data was decommissioned, or
if the node was rebalanced within the decision data node cluster. CAUTION:
The clean up operation causes a temporary spike in disk usage and disk I/O. Do not run this operation during peak usage hours on multiple decision data nodes concurrently, because it affects performance for any process or request accessing the decision data node storage
- Decommission – Removes the node from the decision data node cluster. The data contained in the decision data node storage is transferred to other nodes in the decision data node cluster.