What happens when both nodes are marked offline?

[Marcus Bointon]

In a typical master-master mmm config, what happens if both nodes are marked as admin_offline? Is traffic blocked completely, or does mmm still maintain the IP of the writer role?

Marcus

[sissi]

Hi Marcus,

I think admin_offline status is set by commad line using "mmm_control
set_offline xxx"

in that case, mmm still maintain the IP of writer role, but you can
not ping through that IP anymore unless you set one of the master
online

hope this can help

[Marcus Bointon]

On 14 Apr 2011, at 14:17, sissi wrote:

> I think admin_offline status is set by commad line using "mmm_control
> set_offline xxx"

Yes, that's what I mean.

> in that case, mmm still maintain the IP of writer role, but you can
> not ping through that IP anymore unless you set one of the master
> online

I don't know that that's true. mmm doesn't manage the IP outside of the agent machines (just like heartbeat). Obviously if you tell mmm to take down both nodes it's got nothing left to manage, but I'm just seeking confirmation of exactly what it does with the floating IP. Can someone confirm it please? I don't have a setup I can test that on.

Marcus

[petya]

Hi,

The floating IP won't be configured on any node. Similarly with slaves,
if all your slaves were in admin offline state, none of the reader ips
will be configured.

Peter Boros

[Marcus Bointon]

On 14 Apr 2011, at 17:24, petya wrote:

> The floating IP won't be configured on any node. Similarly with slaves, if all your slaves were in admin offline state, none of the reader ips will be configured.

OK, thanks. When the last node has the writer role and it's set to offline, does it act as if the writer role had been moved, e.g. by setting the node to read-only?

Marcus

[sissi]

Hi，

yap, u r right. when the last master is set to offline, the writer
role is moved, and it is set to read-only, so both masters are read-
only

--sissi