I wonder if there is any limit on the number of NICs (VLANs) in a guest VM using AHV \ AOS?
As well as, what would be the implications of a VM with multiple NICs, for example, over 20 NICs.
Best answer by Paul Ilavarasu
vNICs per VM: You’re limited by virtual PCI bus space, and the limit varies based on VM configuration. There are 32 slots total, one goes to the scsi controller, another goes to the IDE controller (if you have an CD-ROM drive, for example), one or two go to USB controllers. You probably usually have ~25 slots free for vNICs or so.
The PCI bus itself (ie on the device side of the PCI controller circuits) is a parallel shared bus - the same 32 address/data + N control wires run to each PCI device on the motherboard, and to each extension slot. There can be a maximum of 32 devices on a PCI bus, although some of them can be a PCI “bridge” that provides a subsidiary PCI bus.
Any limitation on VM hardware is also depend on the Guest OS , if a VM supports then it will be supported by hypervisor
For an Example:
Windows Server 2016 supports 12 total:
- 8 Hyper-V specific network adapters
- 4 legacy network adapters