CentOS FTP Server Backup and Recovery Strategy

1. Pre-Backup Preparation

Before starting the backup, confirm the FTP server software (commonly vsftpd, ProFTPD, or Pure-FTPd) and key directories:

• Data Directory: Stores user-uploaded files (default: /var/ftp for vsftpd, /home/ftpuser for local users).
• Configuration File: Manages server settings (e.g., /etc/vsftpd/vsftpd.conf for vsftpd).
• Log Files: Tracks access/activity (e.g., /var/log/vsftpd.log for vsftpd).

Stop the FTP service to ensure data consistency during backup:

sudo systemctl stop vsftpd  # Replace with `proftpd` or `pure-ftpd` if using other software

2. Backup Methods

2.1 Full Backup (Recommended for Initial/Full Snapshots)

Use the tar command to package all critical files (data directory, configuration, logs) into a compressed archive with a timestamp:

sudo tar -czvf ftp_full_backup_$(date +%Y%m%d_%H%M%S).tar.gz \
/etc/vsftpd/vsftpd.conf \
/var/ftp/ \
/var/log/vsftpd.log

This creates a single file (e.g., ftp_full_backup_20251022_1430.tar.gz) containing all essential data.

2.2 Incremental/Differential Backup (Space-Efficient for Regular Updates)

• Incremental Backup: Only backs up files changed since the last backup (any type). Use rsync with the --link-dest option to save space:

  sudo rsync -avz --link-dest=/backup/ftp_last_full /var/ftp/ /backup/ftp_incremental_$(date +%Y%m%d)
  

• Differential Backup: Backs up files changed since the last full backup. Use rsync without --link-dest:

  sudo rsync -avz /var/ftp/ /backup/ftp_differential_$(date +%Y%m%d)
  

2.3 Automated Backup with Cron

Schedule regular backups using crontab. For example, run a daily full backup at 2 AM:

sudo crontab -e

Add the following line (replace /path/to/backup_script.sh with your script path):

0 2 * * * /bin/bash /path/to/backup_script.sh

The script should include steps for compression, timestamping, and remote storage (see 2.4 Remote Storage).

2.4 Remote Storage (Disaster Recovery Focus)

Transfer backups to a secure offsite location (e.g., cloud storage, remote server) using scp or rsync:

sudo scp /backup/ftp_full_backup_*.tar.gz user@remote_server:/remote/backup/path/

Or use rsync for incremental sync:

sudo rsync -avz /backup/ftp_incremental_*.tar.gz user@remote_server:/remote/backup/path/

3. Recovery Steps

3.1 Stop FTP Service

Prevent data corruption during recovery by stopping the service:

sudo systemctl stop vsftpd

3.2 Restore Data

• From Tar Archive: Extract the full/differential/incremental backup to the original location:

  sudo tar -xzvf ftp_full_backup_20251022_1430.tar.gz -C /
  

• From Remote Server: Download the backup file first, then extract it as above.

3.3 Restore Configuration and Logs

Copy the backed-up configuration file to its original location:

sudo cp /backup/ftp/vsftpd.conf /etc/vsftpd/

Restore log files if needed (note: logs may be overwritten by the service after restart):

sudo cp /backup/ftp/vsftpd.log /var/log/vsftpd.log

3.4 Verify Permissions

Ensure files and directories have correct permissions (data directory: 755, files: 644):

sudo find /var/ftp -type d -exec chmod 755 {} \;
sudo find /var/ftp -type f -exec chmod 644 {} \;

3.5 Restart FTP Service

Bring the server back online:

sudo systemctl start vsftpd

4. Backup Strategy Recommendations

• Full Backup: Perform weekly (e.g., every Sunday) to create a complete snapshot.
• Incremental/Differential Backup: Run daily (e.g., Monday–Saturday) to save time/space. Combine with full backups to reduce recovery time.
• Retention Policy: Keep full backups for 1–3 months, incremental/differential backups for 1–2 weeks. Delete old backups to free space.
• Test Restorations: Periodically restore backups to a test environment to verify integrity.
• Monitor Backups: Use tools like cron logs or backup software notifications to ensure jobs complete successfully.
• Secure Backups: Encrypt backup files (e.g., using gpg) and store them in a secure location (e.g., encrypted cloud storage).

By following this strategy, you can protect your CentOS FTP server data from loss and ensure quick recovery in case of failures.