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Tech question @JamesNT or @Sandeep

Fast SSD drives look good on the 2019 Hyper-V Host tested via Cyrstaldiskmark. Assign only VHDX file on the SSD to the VM. Within the VM, IOPS and Random 4kQD1 performance drops by about 40-50%. Sequential performance only drops 10%.

Tried QOS settings, tried turning off any other VMs, tried IObalance registry settings. Nothing allows less drop in performance going from host to client. Is there a way to get closer to native IOPS in a VM?

SSDs tried: Samsung 970 Pro and Optane 905p both very fast sustained low queue depth (SQL type load). Both through a PCIE adapter card.

btw Optane 905p 960gb is now on sale for $400. Very fast for database applications. Also there is a reddit story of a signficant number of Samsung 980 Pros going bad after 6-12m of use -- I had one fail with massive bad sectors. Fortunately not on my server.

What hard drive controller are you using? You can have the best SSDs but if your controller card can't keep up, you'll see the problem you have now.

JamesNT

No add-in controller. Motherboard intel RSTe driver AHCI no raid. PCIe to u.2 card in top slot with 905p attached.

NVMe default Microsoft drivers. Defender antivirus off while testing on host and VM.

Hyper-V host testing yields performance as expected

Is there always a 50-60% drop from host storage performance to storage within the VM?

What is the host operating system? This is starting to sound like a workstation.....

JamesNT

Hyper-V 2019.

Lenovo TS140 old system but reasonably fast for 1-2 VMs. E3-1246v3 4c8t 3.5ghz. 32gb ram.

Instead of data center Intel SATA ssds with which I have had great reliability, I'm trying out the 905p and 970 pro consumer SSDs to see if speeds up AC.

Any other ideas that would appreciable accelerate AC? I think 2.5Gb NIC might be next on my upgrade path. Whole server if someone tells me that's what's holding my performance back. I think AC software is the actual bottleneck...

I'm mostly familiar with Dell servers and their hardware. What I can tell thus far is the model server you have came out in 2013. That is before SSDs became mainstream.

Using the comparable Dell R710 (2010) and R720 (2013) I found that while SSDs do increase performance, it's simply not to the point of a more modern computer with a modern hard disk controller. The Dell R740s I have recently installed make the 12GBs SAS SSD drives it has in it literally

S C R E A M.

If you want to take full advantage of SSD, have a more modern hard disk controller - at least 2017 or higher.

James

@ JamesNT interesting thanks!

2 questions:

Likelyhood hardware improvements make a difference in AC performance for small office? (or mostly AC software limiting responsiveness)

Generally does disk performance within a Hyper-v VM take a 40% penalty vs on the host Could you test on your lab system? I haven't found this documented anywhere other than a number of users pointing it out and saying no way around this.

1. Yes, hardware improvements will make a difference in AC performance. However, as Bert, myself, and others have mentioned you will reach diminishing returns at some point because of AC itself.

2. Absolutely NOT. Hyper-V is one of the two PREMIER virtualization platforms (VMWare being the other) and no such penalty exists. The penalty for running VHD or VHDX files as your virtual disks is nearly indistinguishable from using regular drives.

JamesNT

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