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I have a 3 node (1 dir, 2 RS) LVS-DR test set up, which works perfectly
fine. I am using it to load balance VoIP calls (SIP only).
My set up:
kernel: 2.6.8.1
ipvsadm vesion: 1.24-102
ipvs version: 1.20
services: all are non-persistent UDP (right now I have 2 services
configured)
I have few question:
1. The load balancer works fine the way I expected for one one thing:
Sometimes after heavy load surge (500 UDP packets per sec. on the same
connection) , the output of ipvsadm -l -c shows active UDP connections
even if there is no traffic and I stop sending any UDP packets.
In ipvsadm, the default UDP connection timout is set to 300 sec (I did
not change that. I did not even use persistant flag). I expect these
connections to go away after 300 seconds. But after the 300 sec timer
expires, it gets reset to 60 sec and these active UDP connectiosn stay
forever. What could be the reason?
I have noticed from the ip_vs code (ip_vs_conn.c) that there are 2
functions implemented to expire a connection:
ip_vs_conn_expire (This one resets the timer to 60*Hz if the reference
count for this connection is greater than 1 or these is error deleting
connection from hash tab)
ip_vs_conn_expire_now (Deletes the connection immediately)
The function called after timer expires is ip_vs_conn_expire and not the
second one. Why is this so?
2. There is no option in ipvsadm to flush these connections as well. how
can I flush these connections?
There is already a function implemented in ip_vs code to flush all
connections but there is no socket option provided there do the same.
The only socket option to flush is to flush the rules and not the
connections. Why is it so?
3. I tried to enable the debug flag for ipvs in sysctl but doesn't seem
like ipvs was build with debug flags on. How can I turn on debugging for
ip_vs?
Ashish Jain
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