Re: [Sequoiadb-discuss] Sequoia replication

[Emmanuel C. <ma...@fr...>]

Hi Heshel,
> I have a couple of questions concerning the replication of Sequoia. 
> Some background info, we have two locations that we are in the process 
> of setting up. In each location will be two controllers, currently 
> sitting on the same box as the application server. These controllers 
> then have one or more PostgreSQL database boxes for backends. We will 
> also be setting up a pair of switches for the internal communications 
> in each location. Hopefully the duplication will allow me to sleep 
> soundly if we ever have a piece of hardware fail.. ;) We are running 
> FreeBSD for the under lying OS, and the binary of Sequoia 2.10.10.
>
> First, I am attempting to use a dedicated link between the controllers 
> in the same physical location, however I cannot see to get the 
> controllers to use the IP of this interface for replication. I will be 
> removing my current configuration and starting fresh in hopes that it 
> may just be an error in them, but I thought I would also ask here if 
> can it be done while I work that out.
You can force which IP address you want the controller to bind in the 
controller configuration file.
> Second, I did have a working configuration for using a single nic for 
> all communication, however, there was some issues with it. The 
> controllers would disconnect shortly after forming the cluster, upon 
> checking my logs they were using ports outside of what I had 
> configured the hedra/jgroups configuration files for. I had configured 
> the controllers to use 7900 as the communication port, which they did 
> use, but none of the other ports were defined by myself to connect to. 
> (This is a reason I am looking at the separate interface for the 
> controller communication, as opening pf right up on the main 
> interface(s), or turning it off is not an option. However, having a 
> crossconnect between the two servers that is unhindered is acceptable.)
Are you sure that the controller is using your configuration file? It 
will use the first one it finds in the classpath.
> Third I am required to setup replication between 2 physical locations. 
> Since the plan is to use Sequoia for replication in each location, 
> there have been talks of using it for the wan replication as well. I 
> am curious about peoples experience with such a setup. As another 
> possibility, I have been looking into the use of the tungsten 
> connector between the controllers at each site.
For Tungsten, I guess you will have to ask on the Tungsten mailing list. 
I have not been following their development closely (shame on me) and I 
am not sure how this would work.
You can try to setup a tunnel for the group communication between the 2 
sites but latency is probably going to be a penalty. Another option is 
to use the remote controller as an additional backend of the local 
controller.
> Some additonal questions;
>
> FreeBSD rc scripts? I did some digging in the past to see if this was 
> possible, found some talk of it but nothing more.
There are some scripts for Linux but nothing for FreeBSD as far as I know.
> Probably a very common question, new releases of Sequoia? I know 
> working is being done on 4.x, and possibly 2.10.11? Just curious if 
> there is any timelimes?
Sequoia 2.10.11 if it ever comes out will be provided by Continuent. Not 
sure if this will ever happen.
Sequoia 4 relies on me. I have been very busy with my 2 other jobs 
recently and I have had no time to make progress. I have to make a new 
release (probably a beta), if possible this month, otherwise in June. 
The problem is that I have to redo the documentation and that will take 
time. Also I have no access to the test suite that was developed at 
Continuent so the debugging phase might be more painful.

Keep us posted with your progress.
Emmanuel

-- 
Emmanuel Cecchet
FTO @ Frog Thinker 
Open Source Development & Consulting
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Web: http://www.frogthinker.org
email: ma...@fr...
Skype: emmanuel_cecchet