HA

[Alan Robertson]

Scott LaLonde wrote:
> 
> Alan,
> 
> I'm running RedHat 6.2 HA in a two node failover enviroment.
> I currently have both connected into a 10/100 hub in my DMZ.
> I would like to move them to a BayNetworks 450 switch.  But
> whenever there is a failover condition the VIP is associated with
> the mac address of the primary and doesn't move over to the
> backup.    I assuming that HA software is suppose to flush the
> arp table on the switch but doesn't seem to work.   Is this a
> problem with the switch or the HA software?

If I understand you correctly, then it's a bug in the switch.

You said it "doesn't move over to the backup".  By this do you mean that the
IP address isn't taken over by the secondary, or do you mean that the IP
address has been taken over, but it doesn't seem to have had any effect? 
I'm assuming that this latter problem is the one you're seeing.

It's funny you should write just now.  This morning I got a detailed report
on this problem from some guys in Japan.  They were having trouble with a
Bay switch, and invented a much nicer workaround for at least their
particular case.

They changed the gratuitous ARP reply to an ARP request, and their switch
was much happier.  What I did was changed the code to send *both* an
broadcast ARP request and a broadcast ARP reply.  This should make everyone
as happy as they're going to get.

If you want to try the new ARP code, it's in the 0.4.9.0h beta which is now
on the web site.  This beta looks quite stable, and seems to test out
nicely.


	-- Alan Robertson
	   alanr@unix.sh