Dear all,

This is my first post on this list, I hope this is the right forum for it…

On a router cluster I have a number of IP resources for IPv4 and IPv6 VLANs. 
The cluster is implemented with corosync and pacemaker on Debian Wheezy 
systems, with resource-agents version 1:3.9.2-5+deb7u1.

The IPv4 resources are implemented by /usr/lib/ocf/resource.d/heartbeat/IPaddr2.
The IPv6 resources are implemented by 
/usr/lib/ocf/resource.d/heartbeat/IPv6addr.

When the active router dies, the resources are moved to the other node. The 
IPv4 address resources are activated immediately, within a few milliseconds. 
The IPv6 address resources however take about 7 seconds each to start.
I have investigated why this takes so long:

-          first the address is assigned to the interface,

-          then a check is performed to see that the address is really active. 
This means that max 5 pings are done, waiting 1 second after each ping, until a 
response is received (which happens usually after 2 seconds),

-          and then 5 seconds are spent sending unsolicited advertisement 
packets to the neighbours.

The IPv4 address only sends ARP messages after the address assignment is made, 
but defaults to sending them in a background task.

Can anyone explain to me the design choices made here? Why does it take so long 
to start a IPv6 address resource? I had to increase the number of process 
children in corosync (responsible for starting the resources, defaults to 4) to 
get all the IP addresses started in a reasonable time (say 1 second), because 
in the initial default configuration, starting a lot of resources is blocked 
while waiting for the IPv6 address resources…

--
Best regards,
Reinier Boon
________________________________

Reinier Boon | Senior software engineer | Telecats bv | KvK Enschede 06069106 | 
Tel: +31 53 488 99 26 | Fax: +31 53 488 99 10 | E‑mail: 
[email protected]<mailto:[email protected]>



--
Met vriendelijke groet,
Reinier Boon
________________________________

Reinier Boon | Senior software engineer | Telecats bv | KvK Enschede 06069106 | 
Tel: 053 488 99 26 | Fax: 053 488 99 10 | E‑mail: 
[email protected]<mailto:[email protected]>

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