Rate Limiting

[lhall]

Hello,

I've recently wanted to apply rate-limiting to a particular VM and have set it to 4 MB/s however I can see from prometheus graphing that this VM still hits upwards of 25 MB/s for at least 3 or 4 minutes each morning.

Likewise, we have two Proxmox Backup servers and on these I've configured rate-limiting as

"All Clients: 50 MiB with 25 MiB Burst"

however I'm seeing backup traffic going up well in excess of 200MiB each night.

Is there something I'm missing regarding how to configure these traffic limits? The HVs and the backup servers have 4x1G links in 802.3ad bonds.

pveversion
pve-manager/7.1-10/6ddebafe (running kernel: 5.11.22-5-pve)

Thanks in advance!

 

[mira]

The first screenshot shows that the limit is ~50MB/s, so that seems to work.
In the second screenshot it uses bits instead of bytes, so if you divide it by 8 you get ~50MB/s.

 

[lhall]

Sorry, should have been clearer with those shots. The first is for the VM set to 4 MB/s and the second is for the backup server traffic. I take your point on the second, but the first doesn't look correct to me. Is it possible to trigger logging on the HVs to identify if/when per-VM limits are reached?

 

[mira]

Where exactly did you set the limits, and which ones?
Could you provide the VM config? qm config <VMID>

 

[lhall]

Thanks. I've set the limit in the VM config against the 'net0' device:

balloon: 512
boot: cdn
bootdisk: virtio0
cores: 2
ide2: none,media=cdrom
memory: 2048
name: XXXXXX
net0: virtio=E6:2A:96:74:9E:75,bridge=vmbr0,rate=4,tag=730
onboot: 1
ostype: l26
smbios1: uuid=5216d6ac-66d6-421d-b4db-01e8f0ccc0bf
sockets: 1
virtio0: Ceph:vm-247-disk-4,cache=writeback,size=45G

 

[mira]

Do you use OVS by any chance?
There's an open bug in our bug tracker: https://bugzilla.proxmox.com/show_bug.cgi?id=3529

 

[lhall]

Thanks Mira, we are indeed using OVS so I suspect this is the issue.