Network Performance Bottleneck

First and foremost a great thumbs up for proxmox that is providing us with such a great virtualisation platform!

Have a question regarding network performance, maybe someone can guide me to identifying where possible bottleneck exists.

I have used iperf to test network throughput using 3 devices namely

- a DELL laptop with a 1 Gb wired NIC running Windows 7
- a PROXMOX machine with a 3 NIC (2 Intel and 1 Realtek) Bonded NIC
- a QNAP NAS machine with 2 NIC bonded NICs

PROXMOX is setup running 2VMs

- OpenVZ UBUNTU install running a mail server with mail store as NFS store on NAS
- KVM BlackBerry BES server with VM image stored on NAS

And found the following results

a) Laptop iPerf Client to QNAP iPerf Server ~ 450Mbits/sec
b) Laptop iPerf Client to PROXMOX iPerf Server ~ 300Mbits/sec
c) Laptop iPerf Client to OPENVZ Guest on PROXMOX ~ 280Mbits/sec
d) NAS iPerf Client to PROXMOX iPerf Server ~ 840Mbits/sec
e) PROXMOX iPerf Client to NAS iPerf Server ~ 940 Mbit/sec

There seems to be good throughput between PROXMOX and the NAS but when a Windows-based machine connects to either one or the other performance falls drastically?

Where would you recommend tweaking?

Hi Udo, laptop uses the Intel 82577LM gigabit ethernet network connection.

Hi Tom, laptop is native not virtualised and it seems that access to PROXMOX host and PROXMOX OPENVZ guest from a Windows machine (not virtualised) which does seem to encounter the slowdown, since between PROXMOX and the NAS speeds are around 940MBit/sec but when a non-virtualised PC accesses PROXMOX host or the OPENVZ guest goes down to a about 300Mbit/sec.

Any indications whether these are good bandwidth figures for aggregated network links?