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Troubleshooting problems when starting or installing DataStax Enterprise.
Problems with starting DSE
Troubleshooting tips for starting DataStax Enterprise.
Error messages when libaio not installed (DSE 6.0 and 6.7)
When the required libaio1 package is not installed.
DataStax Enterprise times out when starting
When starting DataStax Enterprise as a service a timed out message is displayed.
MX4J warning message during DataStax Enterprise installation
MX4j provides an HTML and HTTP interface to JMX and is not necessary to run DataStax Enterprise.
DataStax Enterprise fails to start after configuring authentication
DataStax Enterprise fails when authorization and authentications settings do not match or when external authentication services are unreachable.
JNA fails to initialize
DataStax Enterprise fails to start because JNA fails to initialize properly.
Cannot write to tmp directory
Steps to fix write problem to the tmp directory.
DSE does not start after the DSEFS keyspace is dropped
If manually deleted, the DSEFS keyspace (dsefs) is not automatically recreated by a node restart. Workarounds for recovering from manual deletion of DSEFS keyspaces.
Fixing Linux related problems.
Peculiar Linux kernel performance problem on NUMA systems
Problems due to zone_reclaim_mode.
Nodes appear unresponsive due to a Linux futex_wait() kernel bug
Nodes randomly freeze and become unresponsive for an unknown reason.
Reads are getting slower while writes are still fast
Too many SSTables can cause slow reads on Linux platforms.
Nodes seem to freeze after some period of time
Some portion of the JVM is being swapped out by the Linux operating system.
Nodes are dying with OOM errors
Nodes are dying with OutOfMemory exceptions on Linux platforms.
Nodetool or JMX connections failing on remote nodes
Nodetool commands on Linux can be run locally but not on other nodes in the cluster.
Handling schema disagreements
Check for and resolve schema disagreements on Linux platforms.
Garbage collection pauses
Troubleshooting GC pauses of more than a second, or multiple pauses within a second that add up to a large fraction of that second.
Java reports an error saying there are too many open files
Java may not have enough open file descriptors on Linux platforms.
Insufficient user resource limits errors
Insufficient resource limits may result in a number of errors in DataStax Enterprise on Linux platforms.
No DSE processing but high CPU usage
Extremely high CPU usage but no DataStax Enterprise processing on Linux platforms.
Cannot initialize class org.xerial.snappy.Snappy
On Linux platforms, an error may occur when Snappy compression/decompression is enabled although its library is available from the classpath.
Firewall idle connection timeout causing nodes to lose communication
Steps to configure the default idle connection timeout on Linux platforms.
Using nodetool sjk
Use nodetool sjk mx to gather database information from MBeans.
Troubleshooting topics for DataStax Enterprise Graph.
Inconsistent handling of string vertex/edge ids collections in DSE Graph steps
Inconsistent handling of string vertex/edge ids collections in DSE Graph steps.
Directly querying Graph data with user-defined vertex ids using solr_query results in null returns
Directly querying Graph data with user-defined vertex ids using solr_query results in null returns.
Dropping a graph or a portion of a graph
drop() hangs in the Gremlin console.
Gremlin console hangs or behaves erratically
Tips to use when the Gremlin console hangs or behaves erratically.
Queries sporadically fail with LOCAL_ONE/LOCAL_QUORUM
Queries in multi-datacenter clusters sporadically fail with a replication factor set to LOCAL_ONE or LOCAL_QUORUM.
Consistency level and graph.addVertex()
A consistency level of ONE can cause inconsistent behavior during vertex creation.
Issues creating a graph cluster using Lifecycle Manager (LCM)
LCM incorrectly configures some necessary information for DSE Graph.
Shutting down Studio Gremlin process
Studio can have its state hung because a command in a cell that will not terminate.
Dropping edge property drops edges
For existing graph data created prior to DSE 5.0.5, dropping an edge property might drop the edge.
Creating graph with options while unified authentication is enabled fails
Creating graph with options while unified authentication is enabled fails.
Vertex label not specified in DSE Graph snapshot
If a vertex label is not specified when a graph snapshot is created, the snapshot will be empty.
DSE Analytics
Adding or removing a Spark application, driver, or worker fails if it cannot be written to recovery storage.
Actions to troubleshoot inconsistent DSE Search query results, finding custom files, trace Solr HTTP requests, and use MBeans.
DSE Search node start
Troubleshooting tips to handle startup issues on DSE Search nodes.
Handling inconsistencies in query results
Troubleshooting tips to handle inconsistencies in query results.
Tracing Solr HTTP requests
Troubleshooting tip for queries: tracing Solr HTTP requests.
Using the ShardRouter MBean
Use the ShardRouter MBean to retrieve information and update the list of endpoints.
Using Solr MBeans
The solr/NativeAllocatorStats MBean exposes native memory allocation.
Fixing problems with security.
DSE fails to start
When authentication is enabled, DSE fails to start with error " Unable to create injector".
SSL certificate doesn't match
DSE troubleshooting for SSL certificate doesn't match error.
SSL exceptions occur on start up or no connections
Troubleshooting for SSL connections for client-to-node encryption and node-to-node encryption when exceptions occur on start up or no connections to the DSE database can be established.
Connection errors with cqlsh and other DSE tools
Troubleshooting for permissions when credentials are required.
Tips for resolving problems in DataStax Studio.
Various troubleshooting topics.
Ring view differences
Indicates that the ring is in a bad state.
sstableloader missing rows
The source SSTables used by sstableloader (bulk loader) may not have included all the table data.
Prepared statements discarded
Prepared statements discarded because cache limit was reached.
Purging gossip state on a node
Correcting a problem in the gossip state.
Recovering expired data caused by TTL year 2038 problem
Recover data that was removed due to a TTL timestamp later than the maximum supported TTL date.