Hack #56. Centralize Resources Using NFS

Make recovering from disaster—and preparing for it—simpler by centralizing shared resources and service configuration.

A key goal of all system administrators is to maximize the availability of the services they maintain. With an unlimited budget you could create a scenario where there are two or three "hot standby" machines for every one machine in production, waiting to seamlessly take over in the event of a problem. But who has an unlimited budget?

Standalone machines that store their own local copies of configuration and data can be nice, if you have lots of them, and you have load balancers, and you have a good cloning mechanism so you don't spend all your time making sure all of your mail servers (for example) are identical. Oh yeah, and when you make a configuration change to one, you'll need a system to push it out to the other clones. This could take quite a bit of time and/or money to get right—and this doesn't even touch on the expense of putting backup software on every single machine on your network. I'm sure there are some smaller sites using standard Unix and Linux utilities for backup and nothing else, but the majority of sites are using commercial products, and they're not cheap!

Wouldn't it be nice if a test box could be repurposed in a matter of minutes to take over for a server with a failed drive? Wouldn't it be great if you only needed to back up from a couple of file servers instead of every single service machine?

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