Hi Pokekman,
@Pokekman wrote: What i know is that IRF doesnt need a dedicated stacking module whereas VSF does.
That's not correct: VSF doesn't require any dedicated stacking module (and stacking cable)...you're probably confusing VSF, which use a frontplane stacking approach on standard Ethernet ports, with backplane stacking which, instead, use dedicated stacking module and cable. I suggest you to have a look to this technical webinar about VSF.
IRF and VSF technologies run on different hardware and software platforms. IRF is a virtual switching technology runnning on Comware 5/7 operating system based switch series (it originated during the 3Com era with the XRN technology), VSF instead is a virtual switching technology running on ArubaOS-Switch operating system based switch series. Differences and similarities - as example, both let you to have a single (virtual) Management plane between member switches - can easily be found over Internet (really, there is plenty of documentation about IRF and some about VSF).
Basic IRF concepts are outlined here and also explained on this Technical Whitepaper (a little bit old but explained concepts are really not outdated); IMHO an interesting document to read is the HPE IRF Access/Core to L3 Leaf/Spine Network Deployment Guide (January 2018).
Remember that each HPE Switch series has its own IRF configuration guide so if you want to go deep you should first understand what HPE Comware based switch series you're planning to use for your IRF implementation. At the same time VSF implementation varies (restrictions/requirements) if deployed on well known Aruba 5400R zl2, Aruba 2930F switch series supporting it or if deployed on newer Aruba CX 6300 switch series and it also varies between Aruba 5400R zl2 and Aruba 2930F switch series.