Re:Twitter migrates data to Google Cloud
by _msw_ on Wednesday January 23, 2019 @12:32PM
(#18980358)
Hi! I'm from the EC2 engineering team.
This is a super challenging problem for general purpose virtualization stacks. EC2 has been working to avoid any guest VM interruptions. With the Nitro hypervisor, there are no management tasks that share CPUs with guest workloads.
See more here, including data from a real customer with real-time requirements running on EC2 under the Nitro hypervisor: https://youtu.be/e8DVmwj3OEs?t=1796
Re:Twitter migrates data to Google Cloud
by parasubvert on Thursday January 24, 2019 @09:38AM
(#18989002)
That's a good point, I have seen cases where we've separated a portion of nodes for VSAN or ScaleIO out to a separate cluster to avoid this behaviour on latency sensitive workloads. These nodes don't need a ton of RAM and you'd better have good E-W bandwidth for them, but it's always a tradeoff...
In hyper converged environments the storage and the compute live together on a service mesh and thus some processing is done on the hypervisor to manage storage, those processes don't have an affinity (in the case of vmware for example) so a guest VM core gets suspended for a couple of hundred clock ticks sometimes.