Troubleshooting

How to Install and Configure RabbitMQ on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install and Configure RabbitMQ on RHEL 9

RabbitMQ is a mature, battle-tested open-source message broker that implements the AMQP 0-9-1 protocol. It decouples application components by enabling asynchronous communication through exchanges, queues, and bindings. Producers publish messages to exchanges; exchanges route messages to queues based on routing rules (direct, topic, fanout, headers); consumers subscribe to queues and process messages independently of the […]

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How to Monitor MySQL with Prometheus mysqld_exporter on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor MySQL with Prometheus mysqld_exporter on RHEL 9

MySQL’s built-in metrics are powerful but not easily scraped. Prometheus mysqld_exporter is the standard exporter that translates MySQL status variables, InnoDB engine metrics, and replication lag statistics into the Prometheus exposition format. Combined with Grafana, the mysqld_exporter provides real-time dashboards covering query throughput, connection pool usage, InnoDB buffer pool hit rates, disk I/O, and replication […]

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How to Install and Configure Memcached on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install and Configure Memcached on RHEL 9

Memcached is a high-performance, distributed in-memory key-value cache designed specifically for caching database query results, session data, and computed values. Unlike Redis, Memcached is deliberately simple — it does not support persistence, replication, or complex data types. This simplicity makes Memcached extremely fast and memory-efficient: it uses a slab allocator to eliminate memory fragmentation and […]

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How to Use Percona XtraBackup for MySQL Hot Backups on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use Percona XtraBackup for MySQL Hot Backups on RHEL 9

Percona XtraBackup is the industry-standard open-source tool for online, non-blocking hot backups of MySQL and MariaDB InnoDB databases. Unlike mysqldump, which produces a logical SQL dump and requires more time for large databases, XtraBackup performs a physical backup — copying InnoDB data files directly while MySQL is running, without acquiring table locks that would block […]

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How to Configure MariaDB Galera Cluster on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure MariaDB Galera Cluster on RHEL 9

MariaDB Galera Cluster is a synchronous multi-primary cluster for MariaDB/MySQL that provides true high availability with no single point of failure. Unlike standard primary-replica replication where only one node accepts writes and replicas are read-only, Galera Cluster allows writes to any node simultaneously — all nodes are always primary, always in sync, and always up-to-date. […]

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How to Install ClickHouse Columnar Database on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install ClickHouse Columnar Database on RHEL 9

ClickHouse is a column-oriented database management system (DBMS) designed for Online Analytical Processing (OLAP). Unlike row-oriented databases (MySQL, PostgreSQL) where each row is stored together — efficient for retrieving full records — ClickHouse stores each column separately, making it extremely efficient for aggregation queries that scan specific columns across billions of rows. ClickHouse can process […]

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How to Configure Redis Cluster and Sentinel on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Redis Cluster and Sentinel on RHEL 9

A single Redis instance has two failure modes: if the server goes down, all cached data is lost and every request hits the origin database; and if the dataset grows beyond a single server’s RAM, there’s no built-in way to distribute it. Redis provides two solutions: Redis Sentinel for high availability (automatic failover with a […]

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How to Install Elasticsearch 8 on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install Elasticsearch 8 on RHEL 9

Elasticsearch is a distributed, RESTful search and analytics engine built on Apache Lucene. It stores data as JSON documents in indices and provides near-real-time full-text search, log aggregation, metrics analysis, and complex aggregation queries through a simple HTTP/JSON API. Elasticsearch is the core component of the Elastic Stack (ELK Stack) — Elasticsearch stores and searches […]

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How to Install and Configure SQLite on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install and Configure SQLite on RHEL 9

SQLite is a self-contained, serverless, zero-configuration SQL database engine that stores an entire database in a single file on disk. Unlike MySQL, PostgreSQL, and MongoDB which require a running server process, SQLite is a library that is linked directly into the application — there is no network connection, no authentication, and no administration overhead. SQLite […]

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How to Back Up PostgreSQL with pg_dump and pg_basebackup on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Back Up PostgreSQL with pg_dump and pg_basebackup on RHEL 9

PostgreSQL provides two complementary backup tools: pg_dump for logical backups of individual databases (SQL statements that can be restored to any PostgreSQL version) and pg_basebackup for physical backups of the entire database cluster (exact byte-for-byte copy of the data directory, used for streaming replication setup and point-in-time recovery). pg_dump is the right tool for most […]

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