LVS DR increased "system CPU" and Excessive Network Traffic

[Rob]

Iain Young wrote:
> Hi Folks,
> 
> I've just installed a couple of machines with LVS on, using the
> DR method. I also used the localnode feature, and started the
> sync daemon as master on one, and backup on the other.
> 
> The nodes are functioning both as Director, and Real Servers,
> and now, both machines are:
> 
> a) showing "System CPU" at around 20%, which vanishes if I kill
> LVS.

Is that a configuration that works for other people?

      MasterDirector      BackupDirector
            |                   |
        sync-master ------> sync-backup
            |                   |
       LocalNode(RS)            |
            ^                   |
            |                   |
Client --> DR --------->  LocalNode(RS)

with no separate real servers? I hadn't ever tried that...

Things that might help diag the problem
What is your output from:
ipvsadm -L --daemon (on master and backup)
and
ipvsadm -l -n --stats
and
ipvsadm -S -n

HA config?
if/ip config?
LVS mngmt (ldirector/keepalived/etc) config?

Anything interesting in:
fgrep -i IPVS /var/log/messages

Can you verify that you can see the multicast packets coming from the master 
on the backup director machine using tcpdump or equiv?

> 
> I could move the LAN traffic off to another interface, and a crossover
> cable, but that really only moves the problem, and doesnt sort the
> CPU system issue.

Despite what Sal said, I would definitely do anything you can to separate sync 
traffic from LVS Dir traffic because it will simplify your initial 
troubleshooting - after you find the problem, you can go back to one interface 
or whatever. You can use ifstat or my favorite dstat to monitor traffic per 
interface - dstat can give you net interface details, CPU usage, etc all in a 
single line. Then you can see where the bulk of the traffic is from/to.

With DR unless you have massive inbound traffic or huge overall traffic your 
LVS Director to Real Server traffic should be relatively low.

> 
> 
> Best Regards
> 
> Iain