FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
JNDias
Staff
Staff
Article Id 244634
Description

This article describes how to increase the disk log size of a FortiGate-VM. The procedure will delete all existing logs from the FortiGate. Tested with version: v7.0.9 and v7.2.3

Scope FortiGate Stand-alone FortiGate in Azure.
Solution

This procedure will delete all existing logs from the FortiGate:

  1. (Optional) Export any logs to archive.
  2. Shut down the VM.
  3. Azure:
  • Delete existing Data disk.
  • Add a new bigger data disk.
  • (optional) disable Host Caching.
  • Save.
  1. Power on the VM.
  2. (Optional) Check 'Serial console' for the VM in Azure.
  3. Wait a few minutes as the new disk will be automatically formatted and will be ready to use.

 

Before.

 

JNDias_0-1675346763621.png

 

Shut down FortiGate-VM:

 

execute shutdown

 

Delete existing data disk:

 

JNDias_3-1675347049495.png

 

Create a new disk. 'Create and attach new disk'. Provide the Size disable 'Host caching' and save.

 

JNDias_4-1675347126844.png

 

Power on:

Power on the machine and look at the console. It will take a few min to format the new disk. After that, it will reboot and FortiGate will start using this disk for log.

 

JNDias_5-1675347216237.png

 

Result.

 

JNDias_6-1675347226109.png

 

Optionally, reconfigure log settings to keep additional log days.

 

Note

FortiGate systems allocate 25% of the disk space for system utilities and unexpected quota overflows, leaving around 75% of the disk space usable for log storage.

 

 

Additional related articles:

How to download Logs from FortiGate GUI

Backup logs in plaintext format avoid performing LZ4 decompression

Technical Tip: Configuring Firewall for Log Roll Over when Disk Usage Exceeds 80%