How to Build a Cost Comparison for vSAN
The first key component to building a cost comparison is understanding the requirements, which at a minimum include the design factors listed in the following figure.
Figure 9. vSAN Basic Design Factors
When building a cost comparison, always are compare like storage systems. Comparing for capacity, performance, and availability is key for demonstrating a like-for-like comparison. In addition, take the following factors into consideration:
• Employ only supported hardware components, based on the latest vSAN Compatibility Guide (VCG)
• Factor in operational savings
• Assume conservative consolidation ratios when calculating capacity and IO requirements based on assumptions, as opposed to empirical data
• Include savings on Fibre Channel components where applicable
• Factor in hardware refresh cycles into cost comparison
• Allow for support, warranty, licenses, and maintenance costs as part of the cost comparison
• vSAN policies are assigned on a per-VM or per-VM-disk basis. For instance, one VM with FTT=2 does not require the entire cluster to be FTT=2 (see the following section)
• Calculate the cost of power, cooling, and floor space as part of the comparison
• Consider $/IOPS in addition to $/GB, particularly when comparing to a low-end storage solution with no flash
• The percentage of storage utilization must be factored into effective $/GB paid for storage
