On Thursday, 09/06/2007 at 09:15 EDT, Ronald van der Laan
<[EMAIL PROTECTED]> wrote:

> VM1                                  VM2
> /==================\                 /==================\
> |                  |                 |                  |
> |   /----------\   |                 |   /----------\   |
> |   |  Linux1  |   |                 |   |  Linux2  |   |
> |   \----+-----/   |                 |   \----+-----/   |
> |        |         |                 |        |         |
> |        |         |                 |        |         |
> |   /----+-----\   |                 |   /----+-----\   |
> |   | vswitch1 |   |                 |   | vswitch2 |   |
> |   \--+----+--/   |                 |   \--+----+--/   |
> |      |    |      |                 |      |    |      |
> \=====OSA==OSA=====/                 \=====OSA==OSA=====/
> |    |                               |    |
> |    |                               |    |
> |    |                               |    |
> /--+----+--\                         /--+----+--\
> |  switch1 |-------------------------|  switch2 |
> \----------/                         \----------/

A picture.  May fortune smile upon you forever and ever.

> Normally Linux1 has the common IP address, but when it becomes
unavailable,
> Linux2 should take over.
>
> [snip]
>
> In the situation, were the take over is forcefully (eg, Linux1 has the
IP
> address still registered), something strange happens.
> On VM1's vswitch and OSAs, the common IP address remains registered.
> But on VM2, the vswitch shows the IP address registered, but with a
"local"
> flag and the console of the vswitch controller shows the familiar
"Return
> code E00A from SETIP for IPv4" error, indicating it could not register
the
> IP address to the switch.

This is normal in a Layer 3 VSWITCH, where you have "split brain".  The
host is dead but the network adapter is still responding to ARPs.  This
prevents the other OSAs from (completely) registering the IP as they know
that it is not proper to have two NICs responding to ARPs.

> Does anyone know how to make the IP take over being forwarded to the
real
> switches and then to the other vswitch?

Operate your VSWITCH as ETHERNET (layer 2) and this goes away since IP
addresses are no longer registered in the OSAs and there is no longer a
"split brain".  When the owning host dies, so dies its ability to respond
to ARPs.

Alan Altmark
z/VM Development
IBM Endicott

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