| Weird network problem under load [message #42234] |
Wed, 23 March 2011 10:02  |
dagr
Messages: 83
Registered: February 2006
|
Member |
|
|
Centos 5
kernel - 2.6.18-194.26.1.el5.028stab079.2
vzctl version 3.0.25.2
////////////////////////////////
I have strange issue. My server runs as fileserver (many random reads) and has several VPSs , some for nginx, one for ftp (vsftpd).
It worked good until traffic was about 200mbit.
Since it reached about 300mbit we encountered issue, that ftp server stalls.
It just hangs occasionally on getting dir listing.
I made the experiment.
I launch tcpdump for my client host IP inside VPS and on HN. And i see inside VPS on venet0 , that server sends packet with dir listing to client , but on HN on corresponding interface (eth2) i see that that this packet doesnt go outside. After 30sec or so it can pass eventually , but most times its just times outs. At the same time if i run telnet to same client port from inside VPS, i see no probs, all packets go outside immediately.
It looks like tcpbuffer bottleneck, but we havent any failcnt inside VPS (/proc/beancounters).
Also we havent any traffic shaping or so.
It happens not all the time, and also we havent problem with nginx VPS.
Do you have any ideas, what can be the reason of such behavior?
|
|
|
|
| Re: Weird network problem under load [message #42263 is a reply to message #42234] |
Mon, 28 March 2011 20:00  |
dagr
Messages: 83
Registered: February 2006
|
Member |
|
|
i ve solved the problem.
The issue was, that http traffic suppressed ftp traffic (different VPS). So it worked as if ftp VE had few Mbit bandwidth. It was ok , until number of simultaneous ftp connections reached certain threshold, so they just blocked each other.
When i made traffic shaping rules to gurantee this VPS 20mbit , everything went ok.
|
|
|
|
OpenVZ Forum
Members
Search
Help
Register
Login
Home
