April 30, 2014 | Written by: Yaxiao Liu
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One of my brilliant colleagues told his spouse that cloud is just something similar to renting a car. Although you will have maximum flexibility to choose a car, it is easier.
You probably won’t rent a car by casual choice, if you can. You will consider the size, power and reliability. Reliability means there is a low possibility the car will be broken down during your rental time.
There are enough reasons for using cloud to gain unlimited resources, flexible allocation, low cost and more. However, would you put a business on a cloud that will restart every day? Let’s take a look at cloud reliability.
Reliability, not availability for cloud
When you rent a car, there may be a lot of choices. For example, you may change your choice because you heard that a certain type of car you got was not reliable.
So, reliability means that you could drive your car safely without it breaking down. You will not only believe the benchmark that the vendor tells you, like a ten year warranty.
When I rent a car, I care about the following:
• Is this a brand new car from a brand new company?
• Is the brand one I have heard of having a lower safety record than my own car?
• Can I easily get my rental car replaced if it is broken down on the road?
Technically, I am concerned about the “broken down time” during my rental experience. The “broken down time” will have two sides:
1. What is the possibility of breaking down?
2. How quickly will the car recover from being broken down? Replacements are always preferred.
I could not estimate the real possibility of the car I get breaking down by using mathematical calculations. However, I would like to discover the mean time between failure, or track record, of my car. I would also like to discover the mean time to recovery of my service provider. Then, I could compare it with my own car or some industry reliability standards. If I put too many people inside or drive too fast, the reliability may disappear.
I also noticed that the longer my rental period, the more reliability I would like to have.
It may be the same for renting a computer from cloud, private or public. When I rent a computer or services from cloud, I would like to see that my service will not break down during the time I am using it. If the tasks were to fail, I would also want to know how quickly I could recover.
Reliability for renting a cloud
The longer the period I want use the rented cloud, the more reliability I would like to have. On one hand, I would like to consider the possibility of business during the renting time (the application on-line time) by:
• Tracking record
• Recovery methods and tools
On the other hand, I should “drive” safely with:
• Proper load
• Proper architecture
• Proper application recovery methods
I don’t need the mathematical calculations about the possibility. I just need some kind of reliable computing when measured against industry standards and my expectations.
Reliability may be a better word than availability for users when renting a car or renting a computer. In my next post I’ll talk about my take on what reliability means in a cloud environment. It may be interesting to ask yourself, “Which is more important to me, the reliability or the availability of cloud services?”