[Serusers] Global Failover Server

[Nick Hoffman]

Hi Greger. I have a few questions about the three solutions you've proposed 
in "Failover/redundancy and Scalability Overview" 
(http://www.iptel.org/drupal/failover_redundancy_and_scalability_overview).

> 1. Cacheless usrloc with a mysql cluster as back-end DB combined with
> implementation of the Path header (to find the registrar of a given UA).
> No replication across servers

By "cacheless usrloc", do you mean db_mode(1) for the "usrloc" module?

What do you mean by "implementation of the Path header (to find the 
registrar of a given UA)"?

Would [registration?] replication across servers not be needed because of 
db_mode(1)?

With this setup, can any UA register with any SER?

> 2.  Multiple SER registrars, each with a standalone, local DB and where
> SIP is used to replicate registrations.  By storing replications from a
> peer in a location_peer1 table and then lookup using this table, you can
> route INVITEs to the registrar being able to pinhole the NAT in front of
> a given UA

If each SER has its own local DB, UAs have to register with a specific SER 
rather than any of the available SERs, right?

I'm afraid I don't understand the last sentence you wrote above. Would you 
mind explaining it in a bit more detail please?

> 3. Each SER is connected to a single mysql DB cluster as in #1, but
> since usrloc also is in memory (cacheless usrloc is not used),
> replication is done between the SER servers and save_memory() is used to
> store the location only in memory (the registrar updates the cluster
> with save())

With this setup, can any UA register with any SER?

> Each of these three can be combined with either:
> a. call-id sticky front-end load balancer (commercial or modified LVS)

What is that?

> c. Linux HA creating two and two peers

What is "two and two peers"?

Cheers,
-- Nick
e: nick.hoffman at altcall.com
p: +61 7 5591 3588
f: +61 7 5591 6588

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