Checking the node status
This content applies only to On-premises and Client-managed cloud environments
Check the status of Decision Data Store (DDS) nodes, for example, to troubleshoot Cassandra-related failures listed in Pega logs.
- If you are using Cassandra in embedded mode, perform the following steps:
Starting in Pega Platform version 8.6, the use of an internal Cassandra database is deprecated. On-premises and client-managed cloud systems that have been updated from earlier versions of Pega Platform can continue to use Cassandra in embedded mode. However, to ensure future compatibility, do not create any new environments using embedded Cassandra.
- In the header of Dev Studio, click .
- On the Decision Data Store landing page, ensure
that data correctly replicates across nodes by verifying that the
ownership percentages of all DDS nodes add up to 100%.
Tip: To check the ownership percentage for a selected node, click the status of the node, and then examine the Owns section.
- For both external and embedded Cassandra, check the node state in the nodetool
- In the nodetool utility, run the nodetool status
Result: Nodetool returns a cluster status report, as in the following example:
Datacenter: datacenter1 ======================= Status=Up/Down |/ State=Normal/Leaving/Joining/Moving -- Address Load Tokens Owns (effective) Host ID Rack UN 10.0.52.7 229.36 KB 256 100.0% 69d1a4da-fe18-483f-9ff8-5ffa8af94eca rack1 UN 10.0.52.9 125.13 KB 256 100.0% 1fc331b1-47af-4760-973d-a34903fb0235 rack1 UN 10.0.52.11 103.92 KB 256 100.0% 2ddffb1d-1bf1-4b20-9da9-a305f325826e rack1
Note: The ownership percentages in the nodetool report are different than the percentages shown on the DDS landing page. The nodetool report describes both original data and replicated data, whereas the DDS landing page only refers to original data. For example, for a three-node cluster with a replication factor of 3, the nodetool report returns a 100% ownership for each node; for a four-node cluster with a replication factor of 3, the nodetool report returns a 75% ownership for each node, and so on.
- Ensure that the cluster status report lists all nodes.
- In the -- column, ensure that all nodes
are marked as UN.UN means that the node status is UP and that the node state is NORMAL.
- In the nodetool utility, run the nodetool status command.
- If a node does not have UN status, investigate the
source of the problem, for example, by performing other Cassandra
troubleshooting procedures.For more information, see the Troubleshooting section of the Apache Cassandra documentation.
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