Arp issue on M$ cluster failover

Howdy everyone,

I am having an arp problem on one of my switches, a cat 6509. (Technically I suppose it would be with the MSFC...)

Here's my setup:

M$ Cluster(Vlan1) --> 6509ios 6509cat --> Users(Vlan2)

The switches are flat, both have all Vlans. 6509ios is the gw for Vlan1 and 6509cat is the gw for Vlan2.

We have an M$ cluster set up and being tested, we found that during a failover the systems on the same VLAN seem to be okay with picking up the new MAC address fairly quickly, they miss one ping, but crossing VLAN's does not work until I clear the ARP cache in the switch.

It would appear as if the cluster sends a grat arp and the 6509ios recieves it but the 6509cat never see's it. I'll try to hit it with a sniffer later to be sure.

-- Laugh at your problems; everybody else does.

Reply to
Wil Schultz
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Ah ha, found the exact bug reported:

formatting link
Now, how to fix....

-- Laugh at your problems; everybody else does.

Wil Schultz wrote:

Reply to
Wil Schultz

Ah ha, found the exact bug reported:

formatting link
Now, how to fix....

Well, you could reduce the arp timeout value on the interface that has the MS cluster. This may not be advisable if it is a large segment, but it will reduce the time that the router takes to age out arp entries.

In interface configuration mode: arp timeout

Don't use zero for the amount of seconds, zero tells the router to never age arp entries. Set it to whatever you are comfortable with for failover response time from your cluster. Remember it will be a balance between performance and failover time. Default is 4 hours. So changing to 10 seconds is a big deal. And again, probably not something I would do if this is a large segment.

Kevin

Reply to
Kevin Widner

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