Network slow KVM

NethServer Version: 6.9
Module: KVM

I have created a Windows Server VM, but when I transfer file with Filezilla, it starts with a speed of 60MB/s, and after about 30 second it goes at 4MB/s… why?

Federico Ballarini

I have reinstalled all VirtIO drivers and seems it works…

Update: it’s slow after it pass 60% of file…

Hi @federico.ballarini,

did you try it with another client, maybe it’s a problem of the FTP server.
Did you make a speedtest ( to check if only ftp is affected?
Filezilla also has a speed limit setting…
Do you have high cpu load when using ftp?
Just some ideas.

I think is a disk problem… but I have already installed virtio drivers and disk is virtio… I have to convert it from qcow2 to raw?

yes, it’s recommended for Windows at Proxmox.

Consider using raw image or partition for a partition, especially with Microsoft SQL database files because qcow2 can be very slow under such type of load.


I have to do this also for linux?

No, it’s not explicitly suggested as it is for Windows.

But there are many discussions about that:

I have tried on Linux and its works fine… after Windows finish some operation I will do this.
But I have a question… how can I do snapshot of raw disk?

I’m obtaining an error:

unsupported configuration: internal snapshot for disk vda unsupported for storage type raw

Federico Ballarini

Found this:

From the Proxmox Site:


In order to use Proxmox VE live snapshots all your virtual machine disk images must be stored as qcow2 image or be in a storage that supports live snapshots and is managed by Proxmox VE.



It seems to be not possible: