Playbooks
- Database is slowApplication-wide slowness; queries take much longer than usual and users are complaining.
- Disk / tablespace full'unable to extend', 'disk full', 'log file full' errors; writes are stopping.
- Blocking & lock crisisQueries hang, 'lock wait timeout', many sessions waiting but CPU is low.
- Connection storm (too many connections)'too many connections', 'ORA-00018', 'remaining connection slots reserved' — new connecti…
- Replication lag / stoppedThe standby/replica is falling behind or has stopped completely; read replicas are…
- High CPUServer CPU at 90%+; the whole system is slow and the load average is high.
- Memory pressure / OOMThe OOM killer kills the process, 'out of memory', low cache hit ratio, excessive…
- Transaction log / undo bloatThe transaction log file or the undo/redo area is growing fast; 'log full', 'ORA-01555…
- Deadlock analysis'deadlock detected', 'ORA-00060', 'chosen as deadlock victim' — transactions lock each…
- Database won't open / unreachableCannot connect to the service, 'connection refused', the instance does not start, the…
- Data corruption'ORA-01578', 'page corruption', 'checksum mismatch', 'MISCONF', I/O consistency errors…
- Long-running query / jobA single query/job has been running for hours without finishing; it consumes resources…
- Postgres XID wraparound / autovacuum crisis'database is not accepting commands to avoid wraparound data loss'; autovacuum cannot…
- tempdb contention (SQL Server)PAGELATCH_UP/EX waits, contention on tempdb allocation pages (PFS/GAM/SGAM), general…
- TLS / certificate expired'certificate has expired', 'SSL handshake failed', clients suddenly cannot connect (with…
- Version upgrade / patch rollbackProblems after an upgrade/patch: performance regression, application incompatibility or…
- Elasticsearch red/yellow cluster & unassigned shards_cluster/health 'red' or 'yellow'; unassigned shards; reads/writes restricted or data…
- Clock skew / NTP problemClock differences between cluster nodes; replication/election inconsistencies, 'certifica…
- Oracle Data Guard (physical standby) setupGoal: set up disaster recovery and high availability for Oracle with a physical standby…
- SQL Server Always On Availability Group setupGoal: set up automatic failover and a readable secondary replica for SQL Server with an…
- PostgreSQL streaming replication + automatic failoverGoal: set up a hot standby for PostgreSQL with streaming replication and add Patroni/repm…
- MySQL InnoDB Cluster (Group Replication) setupGoal: set up high availability with automatic failover for MySQL using InnoDB Cluster…
- MongoDB replica set + sharding setupGoal: set up a replica set with automatic failover for MongoDB and extend it to a…
- High availability with Redis Sentinel + ClusterGoal: set up a master-replica deployment with automatic failover for Redis using Sentinel…
- Elasticsearch resilience: replica + snapshot + CCRGoal: build resilience for Elasticsearch with replica shards, dedicated master/data…
- Security hardening: SQL databases (Oracle, PostgreSQL, MySQL, SQL Server)Goal: harden relational databases CIS-style — default accounts, strong password policy,…
- Security hardening: MongoDB / Redis / ElasticsearchGoal: harden NoSQL/data stores CIS-style — authentication, network restriction, blocking…
- Cloud-managed databases (RDS/Aurora/Cloud SQL/Atlas/Azure SQL)Goal: learn the key differences between cloud-managed databases and self-managed installa…
- Database automation with AnsibleGoal: Make database installation, configuration, user and backup tasks repeatable and…
- Database provisioning with Terraform (IaC)Goal: Define database infrastructure (instance, parameter group, network) as code…
- Databases on Kubernetes (operator)Goal: Run the database on Kubernetes with an operator; instead of a bare StatefulSet,…
- Schema migration CI/CD (Flyway/Liquibase)Goal: Manage database schema changes with versioned migration files; apply them automatic…
- Automated backups (pgBackRest/Barman/Xtrabackup/cron)Goal: Automate database backups; build a reliable recovery chain with scheduled full+incr…
- GitOps & blue-green / zero-downtime deploymentGoal: Deploy schema and application changes without downtime; approach zero downtime…