You manage your company's website, which uses a cluster of two servers with a single shared storage device. The shared storage device uses a RAID $1$ configuration. Each server has a single connection to the shared storage and a single connection to your ISP.

You want to provide redundancy so that a failure on a single component doesn't cause the website to become unavailable. What should you add to your configuration to accomplish this?

answer

On each server, add a second network connection to connect the server to the shared storage device.

Reconfigure the disk array in a RAID $1+0$ configuration.

Connect one server to the internet through a different ISP.

On each server, add a second network connection to the internet.