OpenVZ Forum


Home » General » Support » Understanding user_beancounters: tcpsndbuf
Understanding user_beancounters: tcpsndbuf [message #27849] Fri, 29 February 2008 09:02 Go to next message
ittec is currently offline  ittec
Messages: 41
Registered: February 2008
Member
Hi again

Since I modified some values of privvmpages on my Linux OpenVz server with your help, no more problems happens with this parameter.

Today I need to explain to you similar trouble, this time with tcpsndbuf. I read the http://wiki.openvz.org/Tcpsndbuf#tcpsndbufproperly thread in OpenVz wiki and I did the calculation about tcpsndfbuf formula:

http://wiki.openvz.org/images/math/2/e/3/2e3d5c634d4612a3dda5744d4b8671ba.png

Current user_beancounters values:

tcpsndbuf:
barrier -> 5.777.926
limit -> 12.331.526
fail -> 455.979.976

numtcpsock:
barrier -> 1.600
limit -> 1.600

I think the number of fail is very high. Now with this values Im going to follow the formula that appear in wiki web:

limit - barrier >= 2.5 KB * 1600

12.331.526 - 5.777.926 >= 4.000
6.553.600 >= 4.000

Is right, isn't it? So my first interest is about understand why I have a high number of tcpsndbuf. If I think in formula and I did properly, couldn't happen bad performance on this VE. But the true is the traffic graphics show me bad operation.

Can someone bring me some light here ? Confused

Thanks a lot
Re: Understanding user_beancounters: tcpsndbuf [message #27926 is a reply to message #27849] Mon, 03 March 2008 11:52 Go to previous messageGo to next message
xemul is currently offline  xemul
Messages: 248
Registered: November 2005
Senior Member
Quote:

So my first interest is about understand why I have a high number of tcpsndbuf.


High tcpsndbuf means that there are many active (i.e. passing data) TCP connections on the node.

Quote:

couldn't happen bad performance on this VE.


Small tcpsndbuf may cause a small performance degradation even when there's one TCP connection on the whole node. You may increase the one and check.

This limit was designed not to allow a VE users consume too many kernel memory by sending large amount of TCP packets. The difference between limit and barrier is used to provide a minimal speed for TCP connection when all the sockets are active.


http://static.openvz.org/userbars/openvz-developer.png
Re: Understanding user_beancounters: tcpsndbuf [message #27929 is a reply to message #27926] Mon, 03 March 2008 12:38 Go to previous message
ittec is currently offline  ittec
Messages: 41
Registered: February 2008
Member
Ok. I have changed the values of tcpnsdbuf increasing the total. Ill check the failcnt in next days.

Thanks Smile
Previous Topic: ext3 minimum reserved blocks
Next Topic: Quota Problem
Goto Forum:
  


Current Time: Sun Nov 27 19:16:55 GMT 2022

Total time taken to generate the page: 0.00970 seconds