Transparent failover and restore?

[Gregory Block]

On 17 Dec 2004, at 21:09, Brad Fitzpatrick wrote:
> Guys,
>
> If you want to use memcached as a data store instead of a /cache/, then
> use MySQL Cluster:
>
>    http://www.mysql.com/cluster/
>
> It was designed for that, doing the whole redundant storage and 
> two-phase
> commit thing, while memcached was designed to be a cache.
>

No, I think the point is quite simple, actually;

  - we cache things because the cost of generating them is too high to 
do in bulk
  - on large-scale systems, or heavily used systems, the cost of losing 
a server can bring down the system


The problem can be mitigated, with additional runtime overhead by 
clients, with some work to ensure that there's better distribution of 
single items of information within the cache network.  Moving each 
information onto two servers in the network immediately makes the 
entire system less likely to fall over dead; it also reduces the amount 
of "actual" free space in the cluster you add when you add a node, but 
that's just efficiency losses.  People with RAID will already be 
familiar with that kind of logic.

I think there's actually real benefit into looking into a client-side 
solution for this.