[OpenAFS] Openafs failover

Harald Barth haba@kth.se
Mon, 15 Jun 2009 04:03:40 +0200 (CEST)

> The net result is 2-node active/passive failover
> clusters can be equivalent to standalone fileservers in terms of cache
> coherence (assuming proper Net{Info,Restrict} and rxbind
> configuration).

I'm sorry, I just see the situation with X clients that have cached
data with registered callbacks. When now the fileserver dies and is
replaced with the failover one, how and when are these clients
notified or why should they contact the new failover server to inform
themselves when for example some other client rewrites the file that
these X clients still have?

*looking like a "?"*

> there is the pertinent question of where to store the data.  If/when
> partition uuid extensions become supported, the issue becomes
> significantly more complicated because we will likely want the host
> package data to be replicated across every partition in order to
> support partition-level load balancing (which is further complicated
> by the existence of unmounted, unsynchronized, out-of-date clones).

I don't know enough to say anything about what you describe how it works
with dafs, but I think that callback data has to be stored "near" the
data it represents so that it can be moved along with the data.