Q22. A customer has a requirement for 450 TB of block storage to support their tier2 environment where latency is not a concern. The workload is expected to achieve a 4-to-l data reduction.
Which array and capacity configuration is the minimum required to meet their needs?
To meet the customer’s requirement for 450 TB of block storage with a 4:1 data reduction ratio, we need to calculate the effective usable capacity required and select the appropriate array configuration.
Step-by-Step Calculation:
Effective Usable Capacity Needed :
The workload requires 450 TB of logical storage.
With a 4:1 data reduction ratio, the physical storage required is:
Array Selection :
The selected array must provide at least 112.5 TB of usable capacity after accounting for overhead and RAID protection.
Let’s evaluate the options:
A . FlashArray//C40R3 247 TB :
The FlashArray//C40R3 provides 247 TB of raw capacity. After accounting for overhead (typically ~20%), the usable capacity is approximately:Usable Capacity=247TB×0.8=197.6TB.
This exceeds the required 112.5 TB , making it a valid option.
B . FlashArray//C60R3 878 TB :
The FlashArray//C60R3 provides 878 TB of raw capacity, which is significantly larger than needed. While it meets the requirement, it is not the minimum configuration.
C . FlashArray//X70R3 228 TB :
The FlashArray//X70R3 provides 228 TB of raw capacity. After overhead, the usable capacity is approximately:Usable Capacity=228TB×0.8=182.4TB.
While this also meets the requirement, it is more expensive than the C40R3.
D . FlashArray//C60R3 366 TB :
The FlashArray//C60R3 with 366 TB of raw capacity is overkill for this requirement and not cost-effective.
Recommendation :
The FlashArray//C40R3 247 TB provides the minimum required usable capacity while meeting the customer’s needs.
Final Recommendation:
The correct answer is A. FlashArray//C40R3 247 TB .
Reference:
FlashArray//C Series Product Overview :
FlashArray//C Series
Details the capacity and use cases for FlashArray//C models.
Capacity Planning Guide :
Pure Storage Capacity Planning
Provides guidance on calculating usable capacity based on data reduction ratios.
