[Freeswitch-users] HA clustering solution?

[Łukasz Zwierko]

W dniu 27 sierpnia 2008 14:46 użytkownik James Green
<james.green at stealthnet.net> napisał:
> Łukasz Zwierko wrote:
>> OSPF what? What I am talking about was to have TWO FS machines runnig
>> in active- standby mode, without having this configuration displayed
>> to users. Simplest solution for that is having the same virtual IP on
>> both boxes, and directing the traffic to only one of them. OSPF can
>> help with that, still it's not all that is to it. you're going to need
>> heartbeat info, not just link state. I admit the 2 boxes-on one switch
>> is not the best idea, still some means of failure detections,
>> triggering routing changes are vital.
>
> A software monitor on each host could detect faults and ifdown the
> interface, removing that host from the available cluster.
>

External monitoring would be better, system might hang up, interface
could remain up.

> That said, there is no provision to "activate" the new active host in
> this scenario for the purposes of catching any state information. The
> new active host would simply start seeing traffic on the previously
> [near] idle interface. Less than ideal, again.
>

Right you are.
In my opinion the state would have to be updated at all time. It can
not be assumed that the host will have time/means to transfer anything
to new-active host when the crash begins.

>> In the solution that i've seen, only session's in stable state
>> remained active after active-standby switch.
>
> You have managed to get to this point? Be interested in any details.

I've seen a solution similiar to the one we talking about. Two hosts
were connected directly, and the active, updated the secondary all the
time, with sessions of active users (it was not voip solutions, it
was for GPRS traffic inspection). It was a proprietary solution -
Bytemobile MSSP. It a switchover occured (for any reasons), unstable
sessions got lost, active sessions remained active. The IP sharing
worked a bit differently than I described, as the machines exchanged
heartbeat, were not controlled by external monitoring.
>
> It might be nice to have a mechanism to serialize and database module
> states, however it may prove fragile.
>

It's hard but doable. More problem would be with restoring call states
in standby FS (including voice transcoded connections) . And what
about calls being served by external scripts? That's a real challenge!

Ł

> James
>
>
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