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Exam AZ-304 topic 5 question 32 discussion

Actual exam question from Microsoft's AZ-304

Question #: 32
Topic #: 5

HOTSPOT -
You plan to deploy a network-intensive application to several Azure virtual machines.
You need to recommend a solution that meets the following requirements:
✑ Minimizes the use of the virtual machine processors to transfer data
✑ Minimizes network latency
Which virtual machine size and feature should you use? To answer, select the appropriate options in the answer area.
NOTE: Each correct selection is worth one point.
Hot Area:

Show Suggested Answer

Suggested Answer:

Reference:
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/sizes-hpc#h-series

by velasko at Dec. 3, 2020, 9:56 a.m.

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velasko

Highly Voted 4 years, 8 months ago

Correct Answer: - Compute optimized Standard_F8s - Single root I/O virtualization (SR-IOV)

upvoted 72 times

uzairahm007

4 years, 7 months ago

Can you explain the reasoning please?

upvoted 1 times

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cpalacios

4 years, 7 months ago

So the answer shown is totally wrong? If so, can you explain why?

upvoted 1 times

Jinder

4 years, 6 months ago

The correct answer is F series and SR-IOV.

upvoted 1 times

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somenick

4 years ago

Still not clear, why SR-IOV is better than RDMA

upvoted 3 times

pentium75

3 years, 11 months ago

Maybe because Microsoft mentions 'minimizes the use of the virtual machine processors to transfer data' specifically as an advantage of SR-IOV, but does not mention reduced CPU usage in connection with RDMA.

upvoted 6 times

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EgorAivazov

4 years, 6 months ago

Agree with velasko. Correct Answer: - Compute optimized Standard_F8s - Single root I/O virtualization (SR-IOV) Based on the Microsoft's documentation below: https://docs.microsoft.com/en-us/azure/virtual-network/create-vm-accelerated-networking-cli Explanation: Accelerated networking enables single root I/O virtualization (SR-IOV) to a VM, greatly improving its networking performance. This high-performance path bypasses the host from the datapath, *reducing latency*, jitter, and CPU utilization, for use with the most demanding network workloads on supported VM types. Supported VM instances Accelerated Networking is supported on most general purpose and compute-optimized instance sizes with 2 or more vCPUs. These supported series are: D/DSv2 and F/Fs On instances that support hyperthreading, Accelerated Networking is supported on VM instances with 4 or more vCPUs. Supported series are: D/Dsv3, D/Dsv4, Dd/Ddv4, Da/Dasv4, E/Esv3, E/Esv4, Ed/Edsv4, Ea/Easv4, Fsv2, Lsv2, Ms/Mms and Ms/Mmsv2.

upvoted 4 times

EgorAivazov

4 years, 6 months ago

Please disregard my answer. Accelerated networking (SR-IOV) won't meet the requirement. Coreect answer is: 1. High Performance Compute Standard H16r 2. RDMA Reference: Most of the HPC VM sizes (HBv2, HB, HC, *H16r*, H16mr, A8 and A9) feature a network interface for remote direct memory access (RDMA) connectivity.

upvoted 30 times

rdemontis

3 years, 8 months ago

I think provided answers are correct. RDMA is the technology required to minimize CPU utilization (supports zero copy networking). H16r is the best VM to support this technology among the others listed: https://techcommunity.microsoft.com/t5/networking-blog/the-evolution-of-rdma-in-windows-now-extended-to-hyper-v-guests/ba-p/339699 https://techcommunity.microsoft.com/t5/networking-blog/the-evolution-of-rdma-in-windows-now-extended-to-hyper-v-guests/ba-p/339699 https://en.wikipedia.org/wiki/Remote_direct_memory_access#:~:text=In%20computing%2C%20remote%20direct%20memory,in%20massively%20parallel%20computer%20clusters.

upvoted 6 times

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shapgi

Highly Voted 4 years, 7 months ago

Tough question that requires knowing what VM instance size supports SR-IOV vs. RDMA. Given the selection of VM types and features available, the only combination that would work is: * High performance computer Standard_H16r * Remote Direct Memory Access (RDMA) While it's true that SR-IOV would meet the requirement to minimize network latency, SR-IOV is not supported in any of the available VM sizes. Therefore, the right combo is what I listed above. Reference:- https://www.examtopics.com/exams/microsoft/az-301/view/30/

upvoted 35 times

yyuryyucicuryyforme

3 years, 6 months ago

SR-IOV is enabled by enabling Accelerated Networking but all the VMs listed support Accelerated Networking for fastest ethernet. But Infiniband has faster speeds and lowest latency. The only hardware listed supporting Infiniband is H16r, and that one does NOT support SR-IOV but DOES support RDMA. So H16r and RDMA is the MOST correct choice.

upvoted 2 times

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lwslaw

4 years, 2 months ago

* High performance computer Standard_H16r * Remote Direct Memory Access (RDMA) agree,

upvoted 8 times

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reubems

4 years, 2 months ago

Accelerate networking is supported on Standard_E16s_v3 -> https://docs.microsoft.com/en-us/azure/virtual-machines/ev3-esv3-series AND Accelerate networking means SR-IOV enabled -> https://docs.microsoft.com/en-us/azure/virtual-network/create-vm-accelerated-networking-cli " Accelerated networking enables single root I/O virtualization (SR-IOV) to a VM, greatly improving its networking performance. " So the answer would be SR-IOV and Standard_E16s_v3.

upvoted 3 times

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reachmymind

Most Recent 3 years, 5 months ago

both RDMA & SR-IOV do bypass CPU, but H16r x RDMA 56 Gb/s looks like the winner even at a per-core ratio. -> High-performance computer Standard_H16r -> Remote Direct Memory Access (RDMA)

upvoted 4 times

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student22

3 years, 9 months ago

Correct Answer.

upvoted 3 times

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waqas

3 years, 9 months ago

Provided Answers are Correct.

upvoted 2 times

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subbu3071988

3 years, 9 months ago

Two of the H-series configurations (H16r, H16mr) carry a second low latency, high-throughput network interface (RDMA) optimised and tuned for tightly coupled parallel computing workloads. Some of the other series which offer low-latency include- Ddv4/Ddsv4 series, Edv4/Edsv4 series, Ls/Lsv2 series and NC series. Amongst the options only H16r offers low latency and has high throughput RDMA (which thereby minimizes use of VM processors for data transfer). So I would go for- 1) HPC Standard_H16r 2) RDMA Ref- https://azure.microsoft.com/en-in/pricing/details/virtual-machines/linux/

upvoted 4 times

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syu31svc

3 years, 10 months ago

https://docs.microsoft.com/en-us/azure/virtual-network/create-vm-accelerated-networking-cli https://docs.microsoft.com/en-us/azure/virtual-network/create-vm-accelerated-networking-powershell Accelerated networking enables single root I/O virtualization (SR-IOV) to a VM https://docs.microsoft.com/en-us/azure/virtual-machines/sizes-hpc#rdma-capable-instances SR-IOV support: In Azure HPC, currently there are two classes of VMs depending on whether they are SR-IOV enabled for InfiniBand. Currently, almost all the newer generation, RDMA-capable or InfiniBand enabled VMs on Azure are SR-IOV enabled except for H16r, H16mr, and NC24r. RDMA is only enabled over the InfiniBand (IB) network and is supported for all RDMA-capable VMs. I would say answer is correct

upvoted 1 times

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souvik123

3 years, 10 months ago

- Compute optimized Standard_F8s - Single root I/O virtualization (SR-IOV)

upvoted 1 times

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Ram9533

3 years, 10 months ago

Correct Answer RDMA https://techcommunity.microsoft.com/t5/networking-blog/the-evolution-of-rdma-in-windows-now-extended-to-hyper-v-guests/ba-p/339699

upvoted 1 times

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crazyaboutazure

4 years ago

Answer is HPC with SR-IOV. see below https://docs.microsoft.com/en-us/azure/virtual-network/create-vm-accelerated-networking-cli

upvoted 1 times

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sh99

4 years, 1 month ago

I would go with SRIOV and F8 only on the basis, they have not mentioned to reduce network latency between two machines in Azure. (at which point you could also pop in the answer of H Series and RDMA).

upvoted 2 times

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MaheshS

4 years, 1 month ago

Given answer is correct. Most of the HPC VM sizes feature a network interface for remote direct memory access (RDMA) connectivity. Selected N-series sizes designated with 'r' are also RDMA-capable. This interface is in addition to the standard Azure Ethernet network interface available in the other VM sizes. This secondary interface allows the RDMA-capable instances to communicate over an InfiniBand (IB) network, operating at HDR rates for HBv3, HBv2, EDR rates for HB, HC, NDv2, and FDR rates for H16r, H16mr, and other RDMA-capable N-series virtual machines. These RDMA capabilities can boost the scalability and performance of Message Passing Interface (MPI) based applications.

upvoted 2 times

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Hank_Qin

4 years, 1 month ago

The first answer is general purpose b8ms as explained below: Accelerated Networking is supported on most general purpose and compute-optimized instance sizes with 2 or more vCPUs.

upvoted 1 times

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ashishg2105

4 years, 2 months ago

A Compute optimized Standard_F8s For this solution we need to ensure “Accelerated Networking” is applied on the virtual machines. The Microsoft documentation mentions the below supported series of Virtual Machines for the enabling Accelerated Networking. These supported series are: D/DSv2 , F/Fs, D/Dsv3, E/Esv3, Fsv2, Lsv2, Ms/Mms and Ms/Mmsv2. B Single Root i/o For Accelerated Networking, we need to enable “Single Root I/O Virtualization (SR-IOV)”

upvoted 2 times

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Omkarrokee

4 years, 2 months ago

Given Answers are Right. https://docs.microsoft.com/en-us/azure/cloud-services/cloud-services-sizes-specs

upvoted 4 times

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czarul79

4 years, 3 months ago

Only two options will support solution to ensure “Accelerated Networking” is applied on the virtual machines. -> Compute Optimized Standard F8s -> Single Root I/O Virtualization (SR-IOV) Explanation: The Microsoft documentation mentions the below supported series of Virtual Machines for the enabling Accelerated Networking & supported series are: D/DSv2 , F/Fs, D/Dsv3, E/Esv3, Fsv2, Lsv2, Ms/Mms and Ms/Mmsv2. Additional, for Accelerated Networking, we need to enable “Single Root I/O Virtualization (SR-IOV)”

upvoted 4 times

pentium75

3 years, 11 months ago

B8ms also supports Accelerated Networking. https://docs.microsoft.com/en-us/azure/virtual-machines/sizes-b-series-burstable

upvoted 1 times

pentium75

3 years, 11 months ago

No, does not, forget my previous comment.

upvoted 1 times

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BigR

4 years, 4 months ago

The discussions are not clear for me. May I know what is the correct answer?

upvoted 2 times

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