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 …

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 …

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 …

Rp_filter is short for reverse path filtering on Linux. We can use this to filter packets on Linux. Here are 5 common questions about rp_filter. What is reverse path filtering? Reverse path filtering is a mechanism adopted by the Linux kernel, as well as most of the networking devices out there to check whether a …

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 …

NFS performance is important for the production environment. In this tutorial, we will review how to use DD command to test local storage and NFS storage performance. Test nfs storage performance on Linux There are some differences between each testing command. We choose dd command in the following example. dd – without conv=fsync or oflag=direct. …

A system is having a single core, and if there is a single process consuming all the CPU Time, then CPU utilization will show 100% utilization. But in case of multi core systems it is not necessary that all the CPU’s are been used for running all processes. In such cases uneven CPU utilization across …

Linux monitoring is not an easy task for Linux admins. Luckily we have open-source software to monitor these metrics now. Today we are going to learn Linux metrics we can monitor using this monitor bundle Telegraf/Influxdb/Grafana. We can monitor the following metrics with TIG system. Monitor Basic OS metrics For Linux system Monitor Application Metrics …

actimeo is a common NFS mount option in Linux. actimeo=0 can make a big performance difference in the production environment. What does actimeo mean in nfs mount? The “actimeo=0” option means turn attribute caching off. The actimeo option actually makes the time duration the nfs client holds the various cache attributes like “acregmin”,”acregmax”,”acdirmin” and “acdirmax” …

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 …