RE: what happens while node is bootstrapping?

[DE VITO Dominique <do...@thalesgroup.com>]

> > De : Tyler Hobbs [mailto:tyler@datastax.com]
> > Envoyé : mardi 16 octobre 2012 17:04
> > À : user@cassandra.apache.org
> > Objet : Re: what happens while node is bootstrapping?
> >
> > On Mon, Oct 15, 2012 at 3:50 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
> > Does it mean that during bootstrapping process only replicas serve
> > read requests for new node range? In other words, replication factor
> > is RF-1?
>
> No.  The bootstrapping node will writes for its new range while bootstrapping as consistency optimization (more or less), but does not contribute to the replication factor or consistency level; all of the original replicas for that range still receive writes, serve reads, and are the nodes that count for consistency level.  Basically, the bootstrapping node has no effect on the existing replicas in terms of RF or CL until the bootstrap completes.
>
> --
> Tyler Hobbs
> DataStax

For the purposes of the consistency optimization, I would have written that the (new) node bootstrapping should receive writes, but also its own replicas (!).

In case of SimpleStrategy, it's obvious that the new node replicas are included into the original replicas. So, it's valid to say "The bootstrapping node will writes for its new range while bootstrapping as consistency optimization" without mentionning the new node replicas.

In case of NetworkTopologyStrategy, after having played with some examples to support my following claim, I suspect the new node replicas are also included into the original replicas. So, I am inclined to say it's valid too to say "The bootstrapping node will writes for its new range while bootstrapping as consistency optimization" without mentionning the new node replicas.

1) In case of NetworkTopologyStrategy, for a bootstrap, is it correct to say that the new node replicas are *always* included into the original replicas ?
(I think Cassandra dev have already proved it).

2) in case of bootstrapping multiple nodes at the same time, the replicas of a new node are *not*always included into the original replicas.
Is it a pb for Cassandra (and then, do we need to bootstrap nodes one by one ?), or is Cassandra able to detect multiple nodes are bootstrapping and to deal with it to fetch data on the right nodes ?

Thanks.

Regards,
Dominique