What happens to larger MTU sizes in regards to packet transmission in VMs?

Larger MTU (Maximum Transmission Unit) sizes can indeed lead to dropped packets in certain scenarios, particularly when there is a mismatch in MTU settings across the network. When the MTU size is set larger than what other devices in the communication path can handle, those devices may not know how to process the larger packets. Consequently, if a larger packet is sent over these networks without fragmentation, the receiving device will be unable to accept it, which leads to packet loss.

In the case of virtual machines (VMs), if the network settings, such as MTU sizes, are not properly configured or standardized across all components, it can easily result in dropped packets. This situation can occur especially in cloud environments where there might be a mix of services and configurations, making it crucial to ensure that all virtual network and physical network components communicate with compatible MTU settings.

While larger MTU sizes can theoretically improve performance by allowing more data to be sent in a single packet, the overall network architecture and configuration must support it. If there are inconsistencies in MTU settings within the network, larger packets are more likely to encounter issues, leading to those dropped packets that can hinder communication and reduce application performance.