[OpenSER-Users] openser + mysql clusters

[Watkins, Bradley]

> -----Original Message-----
> From: users-bounces at lists.openser.org 
> [mailto:users-bounces at lists.openser.org] On Behalf Of 
> Stanislaw Pitucha
> Sent: Thursday, July 17, 2008 5:40 AM
> To: users at lists.openser.org
> Subject: Re: [OpenSER-Users] openser + mysql clusters
> 
> ----- "Sajith T S" <sajith at gmail.com> wrote:
> > How is the overall experience like re. deploying openser with mysql
> > clusters?
> 
> Good enough. Just setup A record pointing at 2 or more api 
> nodes and set them up with virtual ips (heartbeat works quite 
> well...). Openser will recover if one of the nodes fail.
> 

I actually use Linux-HA + LVS + ldirectord, though your suggestion is a less complicated alternative that should work fine.

> > Are there gotchas etc that need to be taken care of?  (For
> > example, a 2006 article [1] says that "The MySQL NDB engine 
> currently
> > runs its database completely in memory. This means that you have to
> > be
> > able to fit your database in memory."  But this is not documented as
> > a
> > limitation in mysql faq.)
> 
> It's a feature and it's in the first sentence of cluster 
> overview: "... enables clustering of in-memory databases" ;)
> Gotchas:
> - don't bother with 5.0 - it's got strange issues
> - 5.1.23 was the last version of 5.1.X with ndb. Now you have 
> to compile carrier grade edition from source.

You are correct that 5.1.23 is that last version that came with NDB built-in, but you do not have to compile from source.

You can download the latest open-source version of NDB Cluster here:
http://dev.mysql.com/downloads/cluster/index.html

One of the new features in 5.1.X/NDB 6.2.x (might've been part of NDB 6.1.x too, I forget) is the ability for VARCHAR columns to only use the memory required to store the value rather than a fixed amount.  Depending on your data, this can save a lot of memory.

Of course, as already mentioned, there is also the possibility to use on-disk tables now though all indexes are stored in-memory.  I will say from my experience that you should spend some time ensuring that your queries use as few non-index columns in the WHERE clause as possible if you go this route.  This probably isn't a problem for the standard OpenSER/CDRTool queries I expect, but just a caveat.

FWIW, I use MySQL Cluster with OpenSER as well as several other open-source applications and can say I'm pretty happy with it.


Regards,
- Brad