Configuration Backup Rotation: Smarter Auto-Backup Management in Firmware 1.35

Zyxel_Lynn

Zyxel firewalls have long supported configuration file management through both manual and scheduled (auto) backups. However, with limited internal storage, managing file capacity effectively is critical. Firmware version 1.35 introduces a new feature—Configuration Backup Rotation—to help automate this process intelligently and prevent storage overload.

Why Backup Rotation Matters

Zyxel firewalls store configuration files in the System > File Manager, but this storage isn't infinite. Here are the key storage constraints:

Constraint	Limit
Max number of config files	65 files
Max size per file	5 MB
Total size of all config files	200 M

Out of the 65 total file slots:

• 3 are reserved (System Default, Startup Config, and Last Good Config)
• The remaining 62 slots are available for manual backups or auto-backups

How Backup Rotation Works

Previously, auto-backup created files until hitting a hard cap (default: 50 files). Beyond that, it stopped creating new backups—no automatic cleanup or overwriting occurred.

With Firmware 1.35, you can now enable Backup Rotation, which allows you to:

• Set a custom maximum number of auto-backup files
• Automatically replace the oldest file when the limit is reached

Example:

If you configure:

• Auto-backup interval: Every 5 minutes
• Backup rotation limit: 3 files

Here’s what happens:

1. First backup at 5:00 PM (file #1)
2. Second at 5:05 PM (file #2)
3. Third at 5:10 PM (file #3)
4. Fourth at 5:15 PM → file #1 is deleted, and replaced with the new one

This rotation continues, ensuring only the most recent 3 files are retained.

Important Limitation: File Count Still Matters

Backup rotation only works if total file count stays under 65.

For example:

• If you already have 60 files in your file manager
• And set backup rotation to 10
• Then auto-backup will create files 61, 62... up to 65
• But at file 66, it will stop with an error, even though your rotation limit isn’t reached

At 65 files, backup rotation does not delete older files. You must stay under the file cap for rotation to function properly.

What You’ll See:

• System logs and event messages will alert you that the max file count has been exceeded.
• No new backups will be created until you manually delete older files or reduce the number of saved files.

Similar Limit Applies to File Size

In addition to file count:

• If the total file size exceeds 200 MB, auto-backups will also stop.
• The same error applies to both manual uploads and scheduled backups.

Best Practices

To fully benefit from the new backup rotation feature:

1. Set a realistic rotation limit (e.g., 10–20 files).
2. Periodically review your file manager to ensure you don’t exceed the 65-file cap.
3. Monitor storage usage to avoid crossing the 200 MB limit.
4. Combine rotation with centralized backup options (e.g., external servers or Secureporter) for long-term retention.

With configuration backup rotation in firmware 1.35, managing your firewall’s auto-backup strategy becomes more efficient and less prone to storage errors. Just remember: rotation helps, but storage caps still apply. Plan accordingly.