NVMe Host vs. Guest Disk I/O Speed Question

[jd0039]

Virtualbox v5.2.2
Host: Windows 10 64-bit
Guest Debian Stretch 64-bit (via Vagrant base box)

My host machine has a new NVMe drive, and i'm not seeing the diskio speedboost i was expecting within my VM
I'm assuming that using a NVMe Storage Controller would help increase throughput on the guest
however, I cannot boot from my VMDK when i switch the controller from SATA -> NVMe

When I enable EFI for the VM, I can only see BLK storage, no FS options appear in the mapping table

Maybe converting a previously SATA controlled Linux install to a NVMe Controlled one isn't possible?
I guess I should try a fresh install on a box from scratch with the NVMe Controlled drive present from the get-go.
Will report back.

Any insights would be more than helpful, I realize this is a cutting edge feature.

Related Forum Thread: viewtopic.php?f=2&t=80142
Related Ticket: ticket/16373

[socratis]

I'm assuming that using a NVMe Storage Controller would help increase throughput on the guest

The controller selected is independent of your I/O throughput. It wouldn't matter if you selected IDE for your guest (with minor details I assume), but generally speaking the choice of the controller on the guest is independent of the actual controller on the host. Just try to measure the speeds on a floppy drive

[michaln]

My host machine has a new NVMe drive, and i'm not seeing the diskio speedboost i was expecting within my VM

Could be that your expectation is simply unrealistic. Hard to tell.

I'm assuming that using a NVMe Storage Controller would help increase throughput on the guest

It won't.

Maybe converting a previously SATA controlled Linux install to a NVMe Controlled one isn't possible?

That is entirely possible, because Linux uses completely different device names for NVMe drives.

[jd0039]

tough to compare apples to apples here,

Host (crystal diskmark, seq. & random)
Read: Max: 3GB/s
Write: Max: 2GB/s

Guest
Read: Max: 1.7GB/s (hdparm)
Write: Max: 2.7GB/s (dd)

update:
Guest R/W Avg 2.7GB/s / 3.2GB/s with Ubuntu GNOME Disks Benchmark (100 x 100MB Samples)

You're right, the SATA controlled disk performs nearly identically as the NVMe controlled one

Definitely better than prior host mechanical HDD

[victorFC]

hi jd0039,

Sorry for reviving an old post, did you have to do anything in order to enable those high speeds? I have an nvme drive on the host that is also used by the vm guest but Im not being able to go over 0.25gb/s whereas on my host Im on about 3000. Thanks

[mpack]

As already mentioned above, VirtualBox does not control the performance of host drives. Regardless of what controller emulation you choose in the VM, the actual performance will be dictated by whatever host drive you locate the VDI on, give or take a few percent for different emulation efficiencies. Ditto for other things where host hardware is responsible for most of the work, e.g. network cards.

An entirely separate problem is: don't bother running timed benchmarks inside a VM (e.g. Crystal DiskMark). The numbers will be nuts because the benchmark tool doesn't know that CPU time is shared.

[akasper]

Hi, I got a similar experience.

Host: Latest Windows 10
RAM: 32GB Host
Two identical VMs 10GB RAM each one on Vmware Workstation latest one on VirtualBox latest.
NVME: ADATA SX8200 Pro 2TB
Windows Host does sustained zeroed 30GB file copy around ~700MB/s
Vmware Ubuntu 20.04 does around 550MB/s
Virtualbox same does around 250MB/s
CPU isn't maxed out in both cases. So is it something around the driver?

Do you want to share your specs, possibly someone can reproduce the issue?
Thanks