Technical Note: How to extend the disk space for log in FortiGate VM Model

[alebay]

Description

This article describes how to extend the disk space for log in FortiGate VM Model.

Solution

For FortiGate VM model in FortiOS version 5.6.x, log share disk with both wanopt and webcache.

From the screenshots below we can see that the disk space for log is only about 20% for the full disk.

Iriz-kvm19 #get hardware status

Iriz-kvm19 #get system status

Similarly, the disk usage can be checked on the FortiGate UI.

By default, wanopt and webcache will occupied about 80-85% of the disk space.

In order to extend the disk space for log, we will need to change the disk size of wanopt and webcace. The minimum hardcoded size that must be assigned to wanopt is 512MB.

To reduce the disk size of wanopt:

Iriz-kvm19 # config wanopt storage

Iriz-kvm19 (storage) # edit Virtual-Disk

Iriz-kvm19 (Virtual-Disk) # set size 512

Iriz-kvm19 (Virtual-Disk) # end

To verify: 

Iriz-kvm19 # get wanopt storage

== [ Virtual-Disk ]

name: Virtual-Disk   size: 512   webcache-storage-percentage: 0

Lastly perform a reboot on the FortiGate unit. After the reboot, we can observed that the disk size for log has increased.