[Linux-cluster] FWD: Question on RH Cluster from a MySQL Customer

[Robert Peterson]

Tom Lane wrote:
> Can someone help out this questioner?  I know zip about Cluster.
> I looked at the FAQ for a bit and thought that what he wants is
> probably doable, but I couldn't tell if it would be easy or
> painful to do load-balancing in this particular way.  (And I'm not
> qualified to say if what he wants is a sensible approach, either.)
> 
> 			regards, tom lane
> 
> ------- Forwarded Message
> 
> Date:    Sat, 24 Feb 2007 15:37:17 +0000
> From:    Ivan Zoratti <ivan at mysql.com>
> To:      tgl at redhat.com
> Subject: Question on RH Cluster from a MySQL Customer
> 
> Dear Tom,
> 
> first of all, let me introduce myself. I am the Sales Engineering  
> Manager for EMEA at MySQL. Kath O'Neil, our Director of Strategic  
> Alliances, kindly gave me your name for a technical question related  
> to the use of Red Hat and MySQL - hopefully leading to the adoption  
> of RH Cluster.
> 
> Our customer is looking for a solution that could provide high  
> availability and scalability in a cluster environment based on linux  
> servers that are connected to a large SAN. Their favourite choice  
> would be to go with Red Hat.
> Each server connected to the SAN would provide resources to host,  
> let's say, 5 different instances of MySQL (mysqld). Each mysqld will  
> have its own configuration, datadir, connection port and IP address.
> The clustering software should be able to load-balance new mysqld  
> instances on the available servers. For example, considering servers  
> with same specs and workload, when the first mysqld starts, it will  
> be placed on Server A, the second one will go on Server B and so on  
> for C,D and E. The sixth mysqld will then go on A again, then B and  
> so forth. If one of the server fails, the mysqld(s) is (or are)  
> "moved" on the other servers, still in a way to guarantee a load- 
> balance of the whole system.
> After my long (and hopefully clear enough) explanation, my quick  
> question is: does RH Cluster provide this kind of features? I am  
> mostly interested in the way we can instatiate mysqld and re-launch  
> them on any other server in the cluster in case of fault.
> 
> I would be very grateful if you could help me or address me to  
> somebody or something for an answer.
> 
> Thank you in advance for your help.
> 
> Kind Regards,
> 
> Ivan
> 
> 
> --
>    Ivan Zoratti - Sales Engineering Manager EMEA
> 
>    MySQL AB - Windsor - UK
>    Mobile: +44 7866 363 180
> 
>    ivan at mysql.com
>    http://www.mysql.com

Hi Tom, Ivan, and linux-cluster readers,

In theory, our Piranha / LVS (Linux Virtual Server) may be used to
load-balance the requests to numerous mysql servers in a cluster.

Our rgmanager can provide the High Availability to fail over
mysql services to other nodes in the cluster if they fail.

However, if the mysqld daemons are all running on a SAN and you're
mysqld daemons are trying to serve data from the same file system, you
probably have a problem.  To share the data/database on the SAN in
one harmonious file system, you could use the GFS file system, but 
"regular" mysql is not cluster-aware (to the best of my knowledge).  
The sum of my understanding about this may be found here:

http://sources.redhat.com/cluster/faq.html#gfs_mysql

Since Ivan works for mysql, perhaps he can clear this up if
it's not accurate.  I'd like to know more about "mysql-cluster"
and how it's implemented.  I'd like to see mysql implemented as
a cluster-friendly app using our cluster infrastructure so they
can effectively compete against Oracle RAC without reinventing
the wheel.  I'd even like to be a part of the effort to make this 
happen.  Hope this helps.

Regards,

Bob Peterson
Red Hat Cluster Suite