Re: Want to know more about the load-balancing

[Gerry Reno]

Jan Kneschke Wrote:
-------------------------------------------------------
>...
> * 1 proxy as load balancers
> ...
> This the most basic setup for the proxy as load
> balancers.
>
> As there is only one load-balancer, it is a SPOF
> (Single Point of Failure).
>

Yes, this is what we do not want.


> ...
> Adding a second proxy solves the problem. But it
> open the question how to does the app access the
> second proxy in case the first one fails:
>
> 1) VRRP and move the virtual IP to the new server
> 2) if the app uses JDBC let it fail-over itself
> (if proxy1 is not reachable, it picks proxy2)
> 3) put a proxy next to the application and let it
> detect that the LB-proxies are down and failover
> 2x [ app -> proxy ] -> 2x [ proxy ] -> 2x [
> mysqld ]
>
> This way the app can stay unchanged and just
> connects to a local proxy. It will know which of
> the proxies is up by tracking the connect() calls
> for success or failure and send the requests to
> the proxy which is up.
>
> $ mysql-proxy \
> --proxy-backend-addresses=10.0.0.2:3306 \
> --proxy-backend-addresses=10.0.0.3:3306
>
> The proxy is tracking the availability of its
> backends for the normal load balancing. If one of
> the backends is unavailable, it is take out of the
> rotation for a while and check back again later.
> This is transparent to the clients.

Yes, understand if a slave goes down you remove it from rotation.
My questions were more directed at what if MySQL-Proxy itself went down.

>
> Using VRRP saves to setup the proxies on the app
> servers and means less latency as only one proxy
> has to be passed.

VRRP would be the preferred solution for us for HA for MySQL-Proxy.
So do we need to implement the VRRP solution upfront of MySQL-Proxy or is it built into MySQL-Proxy? If it is already in MySQL-Proxy, how do we declare it?

>
> Jan

Gerry