Non-constant copy speed

[Buhli]

Hello everyone

I am brand new here in the Proxmox world

Briefly about my environment:
I have a HP Microserver Gen 10 Plus with 4x4 TB HDDs. I have created a RAID 10 (zfs) array with this four disks.


For tests I have installed the following virtual machine (Win 10):





When I downloaded a 5 GB iso file from my Synology nas to the virtual machine, I had a constant download speed of approx 112 MB/s (all good so far).

When I copied the same ISO file from the C drive to the F drive within this virtual machine, I had speeds between 0 MB and 420 MB/s.


To me it looks like when it copies data with a speed of 300 - 400 MB, the hard disk is maxed out and then and the copying process is paused for a while.



Is this behavior due to a misconfiguration? Can I optimize this somehow? Or is the problem here the HDDs?

Many thanks and best regards
Buhli

 

[leesteken]

What drives (make and model) are you using? QLC flash and SMR harddisks slow down on sustained writes and need idle time to recover. There is more than one thread on this forum that warns against using them for VMs (especially with ZFS).

 

[Buhli]

What drives (make and model) are you using? QLC flash and SMR harddisks slow down on sustained writes and need idle time to recover. There is more than one thread on this forum that warns against using them for VMs (especially with ZFS).

Hi leesteken

Thank you very much for your quick reply.

I use the NAS N300 4 TB disks from Toshiba.

Do you really think it is the combination HDDs + ZFS? Because yesterday I had the same behavior when I made the RAID 10 with my hpe smart array p408i-a sr gen10 controller. And wouldn't it have paused like that when I downloaded the ISO file from the NAS?

Thanks and best regards
Buhli

 

[leesteken]

I use the NAS N300 4 TB disks from Toshiba.

Do you really think it is the combination HDDs + ZFS?

It was just a guess as there was no information to rule SMR or QLC out.

Because yesterday I had the same behavior when I made the RAID 10 with my hpe smart array p408i-a sr gen10 controller.

Are the drives still connected to the RAID-controller? It is recommended to not use a hardware RAID-controller with ZFS: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_hardware_2
If you are having the same problem without ZFS, them maybe it is a drive issue? Or a controller issue, if the drives are still connected to the RAID-controller.

Have you tried a Linux VM or large file transfers on the Proxmox host itself instead of a VM? Any errors or other relevant messages in the Proxmox system logs?
I have no experience with those drives or that RAID-controller (or HP Microservers). I assume it is a hardware problem but maybe someone else here knows what else it could be.

 

[Buhli]

It was just a guess as there was no information to rule SMR or QLC out.

Are the drives still connected to the RAID-controller? It is recommended to not use a hardware RAID-controller with ZFS: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_hardware_2
If you are having the same problem without ZFS, them maybe it is a drive issue? Or a controller issue, if the drives are still connected to the RAID-controller.

Have you tried a Linux VM or large file transfers on the Proxmox host itself instead of a VM? Any errors or other relevant messages in the Proxmox system logs?
I have no experience with those drives or that RAID-controller (or HP Microservers). I assume it is a hardware problem but maybe someone else here knows what else it could be.

The exact name of the disks is Toshiba NAS N300 HDWN180. And according to a quick google search, these shoult be CMR. That would be okay, right?

Yes, at the moment the disks are still connected to the HPE Raid Controller. I only deleted the array. I can try connecting the disks directly. No, so far I have only tested with the Windows machine. But I can also test once with Linux.

Or could you recommend a different installation? Or configuration?

Thanks and best regards
Buhli