Appendix A MySQL Router Frequently Asked Questions

A.1. Where do I install MySQL Router?
A.2. Can I run more than one instance of the router application?
A.3. How do I make the router application highly available?
A.4. Does the router inspect packets?
A.5. Does the router impact performance?
A.6. Can I bind the router to multiple IP addresses?
A.7. What is the difference between round-robin and first-available scheduling modes?

A.1.

Where do I install MySQL Router?

You should install the router on the same machine as your application.

A.2.

Can I run more than one instance of the router application?

Yes.

A.3.

How do I make the router application highly available?

Currently, there are no high availability features for the router application. You can use a script or similar mechanism to monitor the router and restart it if needed provided the router has not stopped due to no more servers available to redirect.

A.4.

Does the router inspect packets?

No.

A.5.

Does the router impact performance?

Whenever you introduce a component in a communication stream there will be a certain amount of overhead incurred and is affected heavily by workload. Fortunately, performance testing on the currect release has shown approximately 1% within the same speed as a direct connection for simple redirect connection routing.

A.6.

Can I bind the router to multiple IP addresses?

No, the bind_address option in the configuration file accepts only one address. However, it is possible to use bind_addres = 0.0.0.0 to bind to all ports on the localhost.

A.7.

What is the difference between round-robin and first-available scheduling modes?

Round-robin differs from first-available in that it will cycle through the list of servers specified in the destinations option (or repeatedly query the Fabric cache for a list) in a circular manner retrying servers that may have failed previously while first-available will stop once it reaches the end of the list.

Round-robin scheduling is enabled by using the read-only mode and first-available scheduling is enabled by using the read-write mode.