On a Windows Server 2019 VM on a Proxmox host (7.1-11 PVE, 5.13.19-6-pve kernel) I'm having a strange problem:
The upload to a new Synology DS1621+ is horribly slow (1-3 MB/s). The fun part is, as soon as I start another upload to anything else in the network both uploads become fast. The upload to the DS1621+ increases to 40-60 MB/s and the other upload starts fast and stays fast (with a similar/slightly faster speed) until it's finished. Once it is the former upload to the DS1621+ again drops to 1-3 MB/s.
This is 100% reproduceable and I find it a very particular characteristic. However, it seems near next to impossible to google it. So has anybody with some more network experience an idea at what kind of problem this could hint? And what workaround might help, be it host, guest or even synology based?
Obviously, I tried all kinds of google known workarounds without success: Change between VirtIO and Intel E1000, tx & rx off on the host, tx & rx off on the guest, autotuninglevel=disabled on the guest, large send offload disabled on the guest...
Next to the characteristic from above also noteworthy is:
I am kind of out of ideas so any other input on this would be great!
The upload to a new Synology DS1621+ is horribly slow (1-3 MB/s). The fun part is, as soon as I start another upload to anything else in the network both uploads become fast. The upload to the DS1621+ increases to 40-60 MB/s and the other upload starts fast and stays fast (with a similar/slightly faster speed) until it's finished. Once it is the former upload to the DS1621+ again drops to 1-3 MB/s.
This is 100% reproduceable and I find it a very particular characteristic. However, it seems near next to impossible to google it. So has anybody with some more network experience an idea at what kind of problem this could hint? And what workaround might help, be it host, guest or even synology based?
Obviously, I tried all kinds of google known workarounds without success: Change between VirtIO and Intel E1000, tx & rx off on the host, tx & rx off on the guest, autotuninglevel=disabled on the guest, large send offload disabled on the guest...
Next to the characteristic from above also noteworthy is:
- all other bare metal Windows in the network upload at full speed to the new DS1621+
- the Windows VMs with the problem upload with full speed to an old Synology in the same network
- sometimes, also without another upload, the speed very rarely spikes to full speed for 1-5 seconds just to than drop to its "normal" 1-3 MB/s again
- this happens with all traffic to the new Synology (SMB, rsync cgwin, Active Backup for Business)
I am kind of out of ideas so any other input on this would be great!