This is something of an aggregated re-post of a series of articles that have been published over at Simple Talk.
I’m paranoid by nature. I was the one growing up who, while other boys daydreamed about giant mechanical spiders eating the city, played baseball and wrecked their BMX bikes, was daydreaming about building a house in a mountain that was completely self sustaining, hurricane-proof, earthquake immune and had a helipad and rocket propelled evacuation capsule. In fact, I still dream about my hoped-for mountain home’s solar field, grey water recycling plant, greenhouses and indoor/outdoor pool complete with a waterfall and mutant laser dolphins.
This paranoia has served me quite well in my professional life. I like to team NICs, use multipaths, replicate data, version documents, archive files, etc. and etc. I also like clustering and other forms of high availability. However, while reading a vendor white paper (yes, I read those once in a while) I began to ponder just what was being protected by most HA solutions. After some time given over to thinking, researching and writing about the topic, I was shocked at how little protection most if not all high availability systems provide.
Aside from a technical misunderstanding of HA, there are also some career-based misunderstandings that surround high availability. Some people tend to think that HA can make their career more secure or their bosses appreciate them more or their userbase happier. HA will not, by itself (or even in part, as the case may be), make any of those things happen.
After my study on the topic was over and the dust had settled, I had hacked out four articles that follow in succession with each other to clarify the situation. I list them all out here for a quick reference to the entire series:
- 7 reasons why High Availability will help you fail in even more spectacular ways than ever!
- 7 Career Pitfalls that High Availability Systems Will Not Help a SysAdmin Avoid
- 7 Things that High Availability is Not
- The One Way That High Availability Will Help You
- “High Availability or High Recoverability?” (This article was added in August 2011 as a result of some great comments that were added to this blog post)
If you decide to read any or all of those articles, let me know what you think of my treatment of the topic. I once was a lover of high availability solutions, but after closer inspection, I see the concept as a lot less of the savior that I once did. It’s a very tightly scoped thing that has less potential to save your bacon than you may first think. In fact, in some scenarios it can be a time and money waster that distracts you from where you should really be spending your time making a system more resilient.
Do you agree? Do you disagree? Does your experience dictate otherwise or is it in lockstep with my ideas? Let me know in the comments below.