From 717fcb9c81d2bc3cc7a84a3ebea6572d7ff0f5cf Mon Sep 17 00:00:00 2001
From: doc <doc@filenotfound.org>
Date: Mon, 30 Jun 2025 20:06:28 +0000
Subject: uploading documentation

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+# Database Cluster (baboon.sshjunkie.com)
+
+## Overview
+The database cluster consists of two PostgreSQL database servers hosted on `baboon.sshjunkie.com`. These servers are used to store data for services such as Mastodon and AzuraCast. The cluster ensures high availability and fault tolerance through replication and backup strategies.
+
+## Installation
+Install PostgreSQL on both nodes in the cluster:
+
+```bash
+# Update package list and install PostgreSQL
+sudo apt update
+sudo apt install -y postgresql postgresql-contrib
+
+# Ensure PostgreSQL is running
+sudo systemctl start postgresql
+sudo systemctl enable postgresql
+```
+
+## Configuration
+### PostgreSQL Configuration Files:
+- **pg_hba.conf**:
+  - Allow replication and local connections.
+  - Example:
+    ```ini
+    local   all             postgres                                md5
+    host    replication     all             192.168.0.0/16            md5
+    ```
+- **postgresql.conf**:
+  - Set `wal_level` for replication:
+    ```ini
+    wal_level = hot_standby
+    max_wal_senders = 3
+    ```
+
+### Replication Configuration:
+- Set up streaming replication between the two nodes (`baboon.sshjunkie.com` as the master and the second node as the replica).
+
+1. On the master node, enable replication and restart PostgreSQL.
+2. On the replica node, set up replication by copying the data directory from the master node and configure the `recovery.conf` file.
+
+Example `recovery.conf` on the replica:
+```ini
+standby_mode = on
+primary_conninfo = 'host=baboon.sshjunkie.com port=5432 user=replicator password=your_password'
+trigger_file = '/tmp/postgresql.trigger.5432'
+```
+
+## Usage
+- **Check the status of PostgreSQL**:
+  ```bash
+  sudo systemctl status postgresql
+  ```
+
+- **Promote the replica to master**:
+  ```bash
+  pg_ctl promote -D /var/lib/postgresql/data
+  ```
+
+## Backups
+Use `pg_basebackup` to create full backups of the cluster. Example:
+
+```bash
+pg_basebackup -h baboon.sshjunkie.com -U replicator -D /backups/db_backup -Ft -z -P
+```
+
+Automate backups with cronjobs for regular snapshots.
+
+## Troubleshooting
+- **Issue**: Replica is lagging behind.
+  - **Solution**: Check network connectivity and ensure the replica is able to connect to the master node. Monitor replication lag with:
+    ```bash
+    SELECT * FROM pg_stat_replication;
+    ```
+
+## Monitoring
+- **Monitor replication status**:
+  ```bash
+  SELECT * FROM pg_stat_replication;
+  ```
+
+- **Monitor database health**:
+  ```bash
+  pg_isready
+  ```
+
+## Additional Information
+- [PostgreSQL Streaming Replication Documentation](https://www.postgresql.org/docs/current/warm-standby.html)
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