Very slow host-only (vboxnet0) transfer

[oxoocoffee]

I have host-only setup between my host (10.6.7 x64) and guest (XP x32) when I try to dump database running on host from host (terminal) it takes 2 sec. If I try to dump same database from guest I get 22 sec. First I noticed this with my program that was taking very long time to talk to DB. So db dump was another test to see if it is my program or general speed.

[oxoocoffee]

NAT and hostonly

[oxoocoffee]

here is netstat -I vboxnet0

Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll vboxn 1500 <Link#8> 0a:00:27:00:00:00 0 0 0 0 0 vboxn 1500 192.168.77 192.168.77.1 0 - 0 - -

[Paul Kronenwetter]

You might look at whether TX/RX offloading is enabled for the NIC. On Linux that can be determined by using ethtool -k eth0, as an example. Output could look like: rx-checksumming: on tx-checksumming: on scatter-gather: on tcp segmentation offload: on udp fragmentation offload: off generic segmentation offload: off generic-receive-offload: off

On a guest VM, I've never found a configuration where offloading checksums to the NIC works, and only sometimes does it work on the host. Eg: I've found that a NIC will properly calculate checksums for IPv4 traffic but not IPv6. Disabling offloading fixes these problems very quickly and evidently: ethtool -K eth0 rx off ethtool -K eth0 tx off

Good luck! -Paul

[oxoocoffee]

I am on Mac. Ethtool do not exists (that I know of) on this platform. Interesting info anyway :)

[oxoocoffee]

Still it is a problem under 4.1.8. Any one has idea how to test/diagnose this?

[oxoocoffee]

In Win7 guest network interface (I have two setup) both are showing as 1Gbps speed. I can't figure out is there is a query function from host what is the speed of that interface.

[oxoocoffee]

This is output on running Win7x32 guest with VBoxManage showvminfo

NIC 1:           MAC: 080027527BC7, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0, Promisc Policy: deny
NIC 1 Settings:  MTU: 0, Socket (send: 64, receive: 64), TCP Window (send:64, receive: 64)
NIC 2:           MAC: 08002750E32B, Attachment: Host-only Interface 'vboxnet0', Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0, Promisc Policy: deny

[vasily Levchenko]

One of the way to measure speed of network is iperf, and probably it will be more demonstrative if put here comparison of iperf output for both interfaces in both directions.

[oxoocoffee]

Will do so. Give little time...

[Frank Mehnert]

No response, closing.