Cassandra error Unit cassandra.service entered failed state

We get this error when we start our Cassandra recently. New main PID x does not belong to service, and PID file is not owned by root. Refusing. After checking, we found that it is a bug for cassandra startup file. Error Log for Unit Cassandra.service entered failed state systemctl status cassandra cassandra.service – LSB: […]

How does data distribution work in Cassandra?

Cassandra uses data partitions to distribute data to each node. Partitions are based on the partition keys. Partition function(partition key) = token number. Apache Cassandra Data Partitions Apache Cassandra, a NoSQL database, belongs to the big data family of applications and operates as a distributed system, and uses the principle of data partitioning as explained […]

How to backup Cassandra database ? 14348 Ratings

Apache Cassandra supports two kinds of backup strategies. Snapshots Incremental Backups A snapshot is a copy of a table’s SSTable files at a given time, created via hard links. The DDL to create the table is stored as well. Snapshots may be created by a user or created automatically. The setting (snapshot_before_compaction) in cassandra.yaml determines […]

Troubleshoot Cassandra Read Timeout issue in Linux

Cassandra timeout issue is a complex issue. Today we will review what read timeout mean in Cassandra and how to fix it. what does Read timeout mean in Cassandra cluster? A read request reached the coordinator, which initially believed that there were enough live replicas to process it. But, for some reason, one or several […]

Monitor Apache Cassandra with open-source Software

Apache Cassandra cluster is a distributed system. Monitoring this cluster is not an easy task. There are a few monitoring tools for Cassandra in the market. Most of them are commercial products. Today we are going to use open source software to monitor Cassandra cluster. Monitor Cassandra with TIG System In our env, we use […]

How to change password for Cassandra

The default password for Cassandra is Cassandra. So we need to change it immediately after we install it. We can use this command to change it. Change default password for Cassandra user # cqlsh `hostname` -u cassandra Password: Connected to xxx at xxx-xxx-xxx-2.localdomain:9042. [cqlsh 5.0.1 | Cassandra 2.2.13 | CQL spec 3.3.1 | Native protocol […]