Arbiter Redundancy?

[Breck_Carter]

I'm setting an HA environment and I want to use mirroring with arbiter (to allow automatic failover). I have only two servers available, so I have to put the arbiter in one of them. So, if the server with the arbiter goes down, doesn't that mean that my mirror will stop functioning properly? Is there a way to have an arbiter on both servers. I'm a a total newbie and inexperienced in HA, but if there is no redundancy possible for the arbiter, doesn't the arbiter become a single point of failure?

[Breck_Carter]

Memo to all: This is an important question, one that should be repeatedly asked and answered, so let's see some more upvotes!

(It's important because everyone thinks it at least once... I know I did 🙂

[ian_mchardy]

As Breck and Volker have correctly said, if you aren't using 3 separate machines for the partners and arbiter, you don't have HA. There is no way around this with only two computers.

Note that you could consider using a root server and copy node if you don't care about failover (say for disaster recovery - but you can lose an unbounded number of transactions in that configuration). A root server and a copy node will work correctly with only two computers. Also note (as Breck says), the arbiter server doesn't consume significant resources, so modest hardware is adequate for the arbiter. Finally, one SQL Anywhere server can function as an arbiter for multiple HA systems, even if the arbiter is on modest hardware.

[Breck_Carter]

> root server and copy node

> arbiter for multiple HA systems