[Pacemaker] MySQL-Cluster with Pacemaker

[Yves Trudeau]

Hi Andreas,
    with NDB, you have 3 types of node: SQL which is mysqld, Management 
running ndb_mgmd and data running ndbmtd.  SQL and Management can be on 
the same physical host (cohosting) but you ideally need 2 for HA, the 
ndb_mgmd process is very small and low on resources. Data nodes, for HA 
you need mandatory 2 hosts and they can't be on the same host as the 
Management node.  The Data nodes need a lot of memory since in most 
application, you'll want to use only in memory data (with async persistence)

So, the classic setup is:

2 servers, low memory, SQL + Mgmnt
2 servers, high memory, data

Regards,

Yves


On 12-02-09 03:21 AM, Stallmann, Andreas wrote:
> Hi Yves,
>
> ØNDB requires a minimum of 4 nodes for HA...
>
> I understood that in NDB-Cluster the concept of „nodes” has nothing to
> do with physical (or virtual) hosts but with running instances /
> processes. That’s at least, what can be derived from
> http://www.howtoforge.com/setting-up-a-loadbalanced-mysql-cluster-with-mysql5.1
> and from http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-overview.html.
>
> Too me it looks as if NDB-Cluster is supposed to be set up as a (n>1)+1
> cluster*, where the n>1 hosts can carry mysqld and ndb and the +1 host
> is supposed to carry the mysql cluster manager. Please correct me, if
> I’m wrong of if this setup is possible, but (for some reason) is unwise
> / unstable / unsuitable for productive usage.
>
> Thanks in advance,
>
> Andreas
>
> *The first links speaks of an loadbalanced mysql cluster and thus needs
> two further nodes, which carry the load balancing software.
>
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