Download speed decrease on VMs

T

tincboy

Renowned Member
Apr 13, 2010
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I recently notified while the main server can download ( for example ) a file from other server with speed of 11 MBps but the VMs on that server can only download it speed of 4 MBps maximum,
I've also used e1000 NIC with interl driver on it but no much improvement observed on download speed.

Any suggestion to increase the network speed?
 
your description is just not detailed enough, try to describe your questions more detailed, include example.
 
While I run the command below on Proxmox it download the file with about 11 MBps speed but running it on a CentOS VM on top of the same server the speed decrease to about 4 MBps

Code: 
wget [URL]http://cachefly.cachefly.net/100mb.test[/URL]
--2011-10-15 10:43:44--  [URL]http://cachefly.cachefly.net/100mb.test[/URL]
Resolving cachefly.cachefly.net... 205.234.175.175
Connecting to cachefly.cachefly.net|205.234.175.175|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 104857600 (100M) [application/octet-stream]
Saving to: `100mb.test.2'
100%[=================================================================================>] 104,857,600 11.0M/s   in 9.1s
 
use iperf or similar to benchmark network speed. this difference is not normal, you should get more or less the same speed.

also post the output of 'pverversion -v'
 
tom said:
use iperf or similar to benchmark network speed. this difference is not normal, you should get more or less the same speed.

also post the output of 'pverversion -v'
Click to expand...
How to use iperf ?
pveversion -v output is:

pve-manager: 1.9-24 (pve-manager/1.9/6542)
running kernel: 2.6.35-2-pve
proxmox-ve-2.6.35: 1.8-13
pve-kernel-2.6.35-2-pve: 2.6.35-13
pve-kernel-2.6.32-6-pve: 2.6.32-47
qemu-server: 1.1-32
pve-firmware: 1.0-14
libpve-storage-perl: 1.0-19
vncterm: 0.9-2
vzctl: 3.0.29-2pve1
vzdump: 1.2-16
vzprocps: 2.0.11-2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.15.0-1
ksm-control-daemon: 1.0-6
 
Last edited:
As most of VMs are Windows, is there any way to test it via Windows?
the output of ethtool on that VMs card is:

ethtool tap770i0d0
Settings for tap770i0d0:
Supported ports: [ ]
Supported link modes:
Supports auto-negotiation: No
Advertised link modes: Not reported
Advertised auto-negotiation: No
Speed: 10Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: off
Current message level: 0xffffffa1 (-95)
Link detected: yes
 
Any help?
Windows VMs are too slower than primary server
Doesn't this auto-negotiation: No means there's some issue with network
 
Totally I've found the solution.
in Windows 2003 even using e1000 NIC can't stop decreasing download speed, but applying these registery settings helped me out.
http://www.linux-kvm.org/page/WindowsGuestDrivers/kvmnet/registry

To boost the network performance of a VM using Virtio NIC has greate affect but I noticed network unstablity in Windows 2003 using virtio and that registery tricks, for example while downloding a file RDC and pings were gone away.
Any one notified this unstablity in network with virtio and Registery tricks?
 
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