Flash  Module  Type Total  Usable  (physical)  per  module  (TiB) Total Usable  (physical)  capacity of  the array  (TiB) 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% Small 3.29 32.8 32.8 27.88 39.3 33 45.9 39 52.4 44.5 59 50 65.6 56 72.2 61 Medium 7.77 77.8 77.8 66.13 93.3 79 108.8 109 124.4 106 139.9 119 155.5 132 171 145 Large 16.37 163.7 163.7 139.14 194.4 165 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 Extra Large 16.37 163.7 163.7 139.14 194.4 165 229 195 261.9 223 294.6 250 327.4 278 360.1 306 Actual compression ratio of the stored data from Comprestimator (n:1) Effective  Capacity: 1 1.2 1.4 1.6 1.8 2 2.2 Flash  Module  Type Total  Usable  (physical)  per  module  (TiB) Total Usable  (physical)  capacity of  the array  (TiB) 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% 100% 85% Small 3.29 32.8 78.7 66.9 85.3 73 91.9 78 98.4 83.6 99.9 84.9 99.9 85 99.9 85 Medium 7.77 77.8 186.6 158.6 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 Large 16.37 163.7 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 199.9 170 Extra Large 16.37 163.7 392.9 334 399.9 340 399.9 340 399.9 340 399.9 340 399.9 340 399.9 340 Effective  Capacity: Actual compression ratio of the stored data from Comprestimator (n:1) 2.4 2.6 2.8 3 3.2 3.4 3.6 Figure 10-2 usable capacity to maximum effective capacity per compression ratio Figure 10-1 Usable capacity to maximum effective capacity per compression ratio The yellow marked area in Figure 10-2 reflects the theoretical  maximum effective capacity .  The bold cell line shows when the maximum effective capacity is reached, regardless of  compression ratio. See the best practices document linked here, which will have the most  current information: https://www.ibm.com/support/docview.wss?uid=ibm10735459 Looking at Figure 10-1 max effective capacity for 1:1 at 85% is 139.1 TiB. This should be the  total of provisioned capacity configured on this system. When data is stored, you can check  the actual compression ratio. GLYPH<SM590000> Actual compression ratio is 1.8:1.  GLYPH<SM590000> Installed is AE3 with 8 Medium Flash Modules.(which after RAID give 6 modules worth of  usable capacity). GLYPH<SM590000> Comprestimator was not used and it is not known if data is compressible  GLYPH<SM590000> Installed is AE3 with 12 Extra Large Flash Modules. Example 2 for a different configuration:  Example 1: The following effective capacity calculation is made: usable (physical) capacity (6 x 7.7 TB) x compression ratio 1.8 = 83.16 TiB .  Following the recommendation to not exceed 85% = 70.63 TiB. Chapter 10. Capacity Planning and Monitoring  377