Ah yeah, I remember when a friend's company struggled for weeks with some terrible slowdowns on their Azure-based cloud infrastructure. After hours on hours of

Ah yeah, I remember when a friend's company struggled for weeks with some terrible slowdowns on their Azure-based cloud infrastructure. After hours on hours of support calls and emails and weeks of hair-pulling, everything suddenly went better : after careful interviews with Azure support team, they understood that their VMs were running on hosts in two different racks, and that the link between the racks had just been upgraded from gigabit to 10-gig when the ToR switches were replaced.