The Importance of QoS Within The Cloud

By Lane Inman | May 21, 2019

The Importance of QoS Within the Cloud


When projecting consumption of IaaS cloud resources, it is particularly important to understand the subscribed to service quality over time.  Although some awareness is given to the variability of performance of multiple cloud objects at any given instant, the effects of time on cloud service delivery are not often evaluated.  By regularly monitoring the cloud quality of service, one can observe a fluctuation in the mean quality of service delivery as well as the extremes.  Below is chart indicating the measured performance of a synthetic benchmark on a standard cloud image consisting of 4 CPU and 8 GB Memory. The quality of service delivered during the months of November and December is 80% of the average annual delivery.


For a company providing zero growth, the implications of this chart are significant.  A highly tuned environment may in effect require more cloud based virtual machines to increase or decrease not based on the variance of demand, but the variance of supply.  In less optimized environments, customer experience may be impacted by variability of infrastructure.  Highly tuned auto scale environments will have variable bills not based on overall demand, but fluctuations of capacity. In terms of the bottom line, this could result in an incremental 20% increase in monthly cloud costs. This leaves the planners with a choice to either purchase more expensive oversized virtual machines to reduce variance in cost, or purchase, cheaper machines, accepting variability due to provider quality.


Between Singles Day and Black Friday Weekend it is not unheard of for online retailers to see surges of over 200% []. Budgeting for such surges can at times be a challenge with traditional infrastructure, but the challenge does not go away with modern agile environments. Revisiting the chart above, during November’s retail sales events, the variances are even more impactful. Revisiting the above scenario, this 20% could result in an additional 60% increase in your monthly spend or a significantly lesser customer experience during one of the most important times of the year.




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