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 🙂

[Breck_Carter]

Volker's answer is thorough and complete.

> doesn't the arbiter become a single point of failure?

No, the single point of failure is the single computer being used for the arbiter and one of the partners.

If you can't provide three separate computers, you shouldn't bother with HA.

The SQL Anywhere software costs several times more than a third computer; for example, Dell ships a brand-new Desktop for U$299.00 which is perfectly adequate for an arbiter... overkill actually, since it's got a 1T drive and two USB 3 ports so it could be used for backups.

[Vlad]

Breck, you gave me a good topic to ask you. If the arbiter is a small software, why cannot I run it on a small machine, such as "Raspberry PI"?
Are there prerequisites, what the Arbiter must have (e.g. high throughput network, much RAM, CPU, dark colors etc.)?