| [Solved] First slow ping on CTs [message #32084] |
Fri, 18 July 2008 19:06  |
ulver
Messages: 12
Registered: July 2008
|
Junior Member |
|
|
Hello everyone,
First, sorry for my bad english 
I have a little problem, and i don't understand.
When i ping a VEs, the first ping is very slow.
For example :
PING toto (192.168.1.1) 56(84) bytes of data.
64 bytes from toto (192.168.1.1): icmp_seq=1 ttl=64 time=718 ms
64 bytes from toto (192.168.1.1): icmp_seq=2 ttl=64 time=0.223 ms
64 bytes from toto (192.168.1.1): icmp_seq=3 ttl=64 time=0.284 ms
After, it is good for all pings. If i try few seconds later, it's ok, but after 5mn for example the first ping will be slow again.
When i try on a computer (not a VE), the first ping is often higher than the other, but not ~ 500ms or more (30 ms for example, and after 0.2ms)
I tried with venet device, veth device, and it's the same thing. I try on my local network and over the internet, idem.
With veth, when i erase the arp tables on the VE beetween each ping, the problem happens all time. Is it a clue ?
I use Debian :
Linux 2.6.18-12-fza-amd64 #1 SMP
I have no firewall/iptables on the VE or the HN.
I'd want to know 3 things :
- is it normal to have this ?
- is it possible to correct it ?
- does it affect the performance ? For example, on a web server ?
Thank you very much !
[Updated on: Wed, 30 July 2008 12:43] Report message to a moderator |
|
|
|
|
|
| Re: First slow ping on CTs [message #32268 is a reply to message #32128] |
Tue, 29 July 2008 09:03  |
ulver
Messages: 12
Registered: July 2008
|
Junior Member |
|
|
Hi, thank you for your help.
1) With veth (proxy_arp enabled) and venet :
a) I am inside the VE, I ping any host (not a VE) on the network, the delay happens.
b) I am on any host, I ping any VE, the delay happens.
If I try after another ping, the delay doesn't happen.
2) There is no difference beetween ping toto and ping 192.168.1.1 : the delay happens, i don't think this is a problem of DNS.
3) The /etc/resolv.conf is the same on the HN and the VE.
For example :
nameserver 192.168.1.20
IP of the VE : 192.168.1.1
IP of the HN : 192.168.1.10
I try two solutions with veth :
- with proxy_arp enabled (I follow this tutorial : http://wiki.openvz.org/Virtual_Ethernet_device#Simple_config uration_with_virtual_Ethernet_device). The delay happens.
- with bridge (i bridge eth0 from the host with veth101.0 in a br0) and without proxy_arp, the delays doesn't happen.
So does the problem come from the proxy_arp ?
[Updated on: Tue, 29 July 2008 09:07] Report message to a moderator |
|
|
|
|
|
|
|
OpenVZ Forum
Members
Search
Help
Register
Login
Home
