Re: [Postgres-xc-general] Postgres XC and resiliency.

[Mason S. <ms...@tr...>]

Hi Tim,


On Tue, Apr 8, 2014 at 12:28 AM, Tim Uckun <tim...@gm...> wrote:

> It would be ideal if shards could be distributed amongst the data nodes in
> a redundant fashion. Perhaps with limits like at least three nodes, no more
> than five nodes etc.
>

As mentioned, there is no built-in HA.  While some tables can be
"replicated" there are not redundant copies of the other tables that are
"distributed" (partiioned/sharded). The way to achieve this is analogous to
HA in PostgreSQL; have a redundant copy of each node. In addition,
Postgres-XC adds a a GTM Standby. My company has used Corosync/Pacemaker
for failing over the components for our StormDB branch of Postgres-XC. What
we do is have a replica of node1 on node2 and node3, have a replica of
node2 on node3 and node4, etc.

What you are describing above (shard redundancy policies), is actually what
my employer, TransLattice, offers in its multi-master TED product. It
decouples sharding from the nodes so that it is not a 1-1 mapping. It is
not open source, however.

Good luck!

Regards,


-- 
Mason Sharp

TransLattice - http://www.translattice.com
Distributed and Clustered Database Solutions