Real Storage Summary in Prism doesn't match Sizer/Storage Capacity Calculator

  • 25 June 2020
  • 1 reply

Hi forumpeople,

For some reason we see different values in Storage Summary in Prism and Sizer/Storage Capacity calculator. We are dealing with an RF2 cluster here.

Storage Summary shows 47.9 TiB 

Yet Sizer shows 35,53 TiB

and Storage Capacity calculator shows 36,05 TiB


A small difference may be due to the actual cluster having 4x2TB NVMes per each of the 5 nodes, and only 1.92 being available in Sizer/Capacity calculator, but it should not make such a critical misalignment between Prism and Sizer/Capacity calculator.

What is the actual usable capacity of the cluster (with RF2, N+1)? Also, how are “CVM Overhead” values taken into account in Prism’s Storage Summary and is it part of the actual usable capacity?

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1 reply


The difference is that Prism displays the total storage capacity without taking failover into account but CVM overhead is included in the usage.

You can check the below KB for the calculation for the actual usable capacity of the cluster - with RF2, N+1: