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On Mon, 4 May 2009, Christian Frost wrote:
> After a
> few seconds the inactive connections are represented as active in the
> respective real server. This causes a problem when the Least-Connection
> Scheduling algorithm is used because the connections are not equally
> between the two real hosts. The two real hosts are almost equal in terms
> of processing capacities.
I assume you're using the same kernels etc...
For LVS-DR the number displayed for ActiveConn, InActConn is
completely fabricated (based on expected tcpip timings),
since the director doesn't see the return packets. Changing
the director kernel from 2.4.x to 2.6.x results in dramatic
changes in these numbers, when there is no change in the
realservers. Still I would expect you'd get about the same
numbers if the software was the same on all machines, even
if the numbers aren't an accurate reflection of the state of
the realservers.
When you get the unbalanced situation below, what's
happening on the realservers? Do they have the same number
of connections, loadaverage....?
> In the following the output of ipvsadm -L -n is shown which probably
> explains the problem better.
>
> ipvsadm -L -n a few seconds in the test simulating 200 MySql clients
> connecting simultaneously.
>
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
> -> RemoteAddress:Port Forward Weight ActiveConn InActConn
> TCP 10.0.1.5:3306 lc
> -> 10.0.1.2:3306 Route 1 71 0
> -> 10.0.1.4:3306 Route 1 70 60
>
>
> ipvsadm -L -n after 30 seconds in the test simulating 200 MySql clients
> connecting simultaneously. Note that the load balancer uses the
> Least-Connection scheduling algorithm.
>
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
> -> RemoteAddress:Port Forward Weight ActiveConn InActConn
> TCP 10.0.1.5:3306 lc
> -> 10.0.1.2:3306 Route 1 71 0
> -> 10.0.1.4:3306 Route 1 130 0
>
>
> The problem does not occur if the connections are made sequentially
what does sequentially mean? One at a time and wait till the
client disconnects?
Joe
> and
> if the number of total connections is below about 100.
>
> Is there anything we can do to avoid these problems?
>
> Best regards
>
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
> Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>
--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!
_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/
LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
or go to http://lists.graemef.net/mailman/listinfo/lvs-users
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