Adding more followers while they are catching up

[Asad Awadia <as...@gmail.com>]

Hello,

If I have 1 node raft cluster and I begin adding more nodes to it - how
many nodes can I add if they are still replicating? Is there a limit in
ratis or raft?

Eg
1 Node is up and running and is the leader
2nd node is added and is catching up
At this point can I add more nodes? Will they all continue to independently
replicate from the leader?

Asking because now there are 3 nodes with 2 not up to date - if the leader
goes down they may form their own cluster without having all the data?

Regards,
Asad

Re: Adding more followers while they are catching up

[Tsz Wo Sze <sz...@gmail.com>]

Hi Asad,

> At this point can I add more nodes? Will they all continue to
independently replicate from the leader?

Yes, you can.  They will be independently replicated from the leader.

> ...  if the leader goes down they may form their own cluster without
having all the data?

It depends on whether the setConfiguration log entry is committed.  If they
are still catching up, setConfiguration cannot be committed, then they
cannot form their own cluster.

Tsz-Wo


On Tue, Feb 14, 2023 at 10:51 AM Asad Awadia <as...@gmail.com> wrote:

> Hello,
>
> If I have 1 node raft cluster and I begin adding more nodes to it - how
> many nodes can I add if they are still replicating? Is there a limit in
> ratis or raft?
>
> Eg
> 1 Node is up and running and is the leader
> 2nd node is added and is catching up
> At this point can I add more nodes? Will they all continue to
> independently replicate from the leader?
>
> Asking because now there are 3 nodes with 2 not up to date - if the leader
> goes down they may form their own cluster without having all the data?
>
> Regards,
> Asad
>