How to extend HD logging space?

Dear all,

I'm running a F1500D device with only one vdom "root". I want to give more space for logging but it's default only 30Gb each vdom. How can i do to extend more for logging space? Thanks for your advice!.

Total HD usage: 37037MB/112673MB Total HD logging space: 33802MB Total HD logging space for each vdom: 33802MB HD logging space usage for vdom "root": 31219MB/33802MB