[RADIATOR] Radiator high Availability

[Heikki Vatiainen]

On 08/26/2012 03:00 PM, sergio wrote:
> I use Radiator 4.10 and I need to place a second radiator and I use FreeBSD, but I need a solution to the sessions (SessionDatabase SQL) is well synchronized since I use mysql. A mysql replication via resolves or is there a better solution?

Here are some thoughts:

You should consider cases where the replication master becomes
unreachable. If radiusd switches to secondary DB server, what happens
when the primary comes back?  I am assuming there are two DB servers,
master that replicates to secondary server.

If there's a network connectivity problem with one radiusd and the DB
master server and radiusd decides to switch to the secondary DB. What
happens when there are writes to both DB server.

If the writes can happen to both DB servers, how fast should the
replication be? Assuming you have two radius servers and there's a very
short lived session where the accounting start and stop messages go to
different RADIUS servers which talk to different DB servers, is the DB
synchronised when the session ends? Could session stop be recorded after
session start?

If you try to make replication quicker, how soon will the database start
having load problems.

Note: I'm not very familiar with MySQL synchronisation. There are likely
many other things to consider too.

> I also thought about using FreeBSD with CARP.

CARP seems to allow hosts to share the same IP address. RADIUS requires
certain amount of state to handle e.g., retries and knowing which reply
is related to which request. Sharing an address can lead to problems
when related RADIUS messages are sent to multiple different RADIUS servers.

Thanks,
Heikki

-- 
Heikki Vatiainen <hvn at open.com.au>

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