Technical Tip: How to get the number of disks used for wanopt using SNMP

Enable the WAN optimization on the FortiGate :

config system storage
     edit "Virtual_disk name"

           set usage wanopt

     next

end

The following information can be retrieved by checking the disk partition allocation via Command Line:

diagnose hardware deviceinfo disk

Disk SYSTEM(boot) 2.0GiB type: IDE [Virtio Disk] dev: /dev/vda
partition 231.0MiB, 103.0MiB free mounted: Y label: dev: /dev/vda1(boot) start: 2048
partition 1.6GiB, 1.4GiB free mounted: Y label: dev: /dev/vda2(boot) start: 526336
partition ref: 3 63.0MiB, 62.0MiB free mounted: N label: dev: /dev/vda3 start: 4063232

Disk Virtual-Disk ref: 16 16.0GiB type: IDE [Virtio Disk] dev: /dev/vdb
partition ref: 17 15.7GiB, 15.6GiB free mounted: Y label: LOGUSEDXCED43529 dev: /dev/vdb1 start: 2048

Disk Virtual-Disk2 ref: 32 10.0GiB type: IDE [Virtio Disk] dev: /dev/vdc
partition ref: 33 2.7GiB, 2.7GiB free mounted: Y label: WANOPTXX99A0FAD4 dev: /dev/vdc1 start: 2048 <----- 1 disk for wanopt.
partition ref: 34 2.8GiB, 2.8GiB free mounted: N label: dev: /dev/vdc2 start: 5978112
partition ref: 35 3.8GiB, 3.8GiB free mounted: N label: dev: /dev/vdc3 start: 11954176

Total available disks: 3
Max SSD disks: 8 Available storage disks: 2

Verification via SNMPwalk:

The wad disk count can be checked using the following SNMPwalk command:

snmpwalk -v2c -c test 10.191.19.120 FORTINET-FORTIGATE-MIB:fgDiskCount
FORTINET-FORTIGATE-MIB::fgDiskCount.0 = INTEGER: 1

Note:

The SNMP fgDiskCount.0 OID description is inaccurate, as it represents the count of WAD disks rather than the total disk count. 

The OID is applicable only when the device has a disk reserved for WAN optimization.