System Administrator: Phase 6 Guide

Detailed Explanation: This competency involves Capacity Planning and lifecycle management. By analyzing the monitoring data gathered in Phase 5, the administrator predicts when the server will hit 100% capacity. They must then propose a scaling strategy: Scaling Up (adding more RAM/CPU to an existing server) or Scaling Out (adding more servers to a Load Balancer pool).

Detailed Explanation: Backups are worthless if they cannot be restored. System administrators must regularly test Disaster Recovery (DR) procedures. A system restore might involve recovering accidentally deleted files, rebuilding a corrupted database from a SQL dump, or rolling back a virtual machine to an earlier snapshot to meet the company's Recovery Time Objective (RTO).

Code Snippet: Restoring Web Files and a Database

This snippet demonstrates the two most common restore operations: pulling files from a remote backup server via rsync, and restoring a compressed MySQL dump back into the database engine.

#!/bin/bash
# System Restore Procedure

echo "Initiating Emergency Restore Procedure..."

# 1. Restoring Application Files
# Pulling the web directory back from the remote backup server
echo "Restoring /var/www/html from backup server..."
sudo rsync -avz --progress backup_user@10.0.0.50:/backups/webserver_latest/ /var/www/html/

# Ensure proper permissions after file restore
sudo chown -R www-data:www-data /var/www/html/

# 2. Restoring the Database
# Decompressing the gzip backup and piping it directly into MySQL
DB_NAME="production_db"
BACKUP_FILE="/backups/mysql/production_db_2026-03-20.sql.gz"

echo "Restoring Database: $DB_NAME..."
# Drop and recreate the database to ensure a clean slate (Use with extreme caution!)
mysql -u root -p -e "DROP DATABASE IF EXISTS $DB_NAME; CREATE DATABASE $DB_NAME;"

# Decompress and import
gunzip -c $BACKUP_FILE | mysql -u root -p $DB_NAME

if [ $? -eq 0 ]; then
  echo "Database restore completed successfully."
else
  echo "CRITICAL: Database restore failed!" >&2
  exit 1
fi

echo "System Restore sequence finished. Please verify application integrity."