Error message is the first step to troubleshoot Apache Cassandra issues. That can help us identify if the issue happens on client-side or server-side. Here are the 4 most common Cassandra issues below. Check Cassandra SyntaxError (client) This and other QueryValidationException indicate that the client sent a malformed request. These are rarely server issues and …

We need to add open source Apache node to dse cluster first. After the data sync is done, we can remove dse nodes. Here are the steps about how to add Apache nodes to dse cluster. Version matches please make sure you Install same version OSS Cassandra with your DSE SELECT release_version FROM system.local; release_version …

CREATE USER in Cassandra CREATE USER alice WITH PASSWORD ‘password_a’ SUPERUSER; CREATE USER bob WITH PASSWORD ‘password_b’ NOSUPERUSER; CREATE USER is equivalent to CREATE ROLE where the LOGIN option is true. So, the following pairs of statements are equivalent: CREATE USER alice WITH PASSWORD ‘password_a’ NOSUPERUSER; CREATE ROLE alice WITH PASSWORD = ‘password_a’ AND LOGIN …

No space left on device usually means that we run out of disk space. But in rare cases, we still have some space when we get this error. People will get confused when they get this error. Here is the troubleshooting process about this. “No space left on device” even though there is space # …

Rsync is a unique, full-featured file transfer facility. It can perform differential uploads and downloads (synchronization) of files across the network, transferring only data that has changed. How does Rsync work? Rsync faster than scp or sftp? How to use Rsync to sync files between servers? For example, if there is a local copy of …

No Load balancers in front of cassandra Cassandra distributes the data across the nodes and most of the cassandra drivers have the algorithm built in to direct requests appropriately . Adding load balancer introduces an additional layer , potentially breaks intelligent algorithms used by driver and also introduces a single point of failure where there …

Decrease the default read ahead values in unix/linux systems Most of the modern unix/linux systems use read ahead so that subsequent reads will be cached in to memory . This provides a performance benefit for systems that read data sequentially (e.g. Kafka) .However, in cassandra most normal read operations are not sequential and hence read …

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: …

Sometimes when we ssh to Linux box, we get this error “WARNING: Your password has expired.” You must change your password now and login again! Changing password for user ocp. Changing password for ocp.” What does “WARNING: Your password has expired.” mean? That means the password for this account expired. We need to change the …

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 …