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How can i reduce the dispersion?

I have two storage policies with one ring for account, container and object, and for each ring i have one region and two zones.

Now, i am trying to create another storage policy and one ring for account, container and object with 2 regions and two zones each, but when i create the ring for account i get dispersion over 60%

swift-ring-builder account-2.builder create 9 4 1
swift-ring-builder account-2.builder add r1z1-1.1.5.5:6002/s1-ssd1 65
swift-ring-builder account-2.builder add r1z1-1.1.5.5:6002/s1-ssd2 65
swift-ring-builder account-2.builder add r1z1-1.1.5.6:6002/s2-ssd1 65
swift-ring-builder account-2.builder add r1z1-1.1.5.6:6002/s2-ssd2 65
swift-ring-builder account-2.builder add r1z2-1.1.5.7:6002/s3-ssd1 65
swift-ring-builder account-2.builder add r1z2-1.1.5.7:6002/s3-ssd2 65
swift-ring-builder account-2.builder add r1z2-1.1.5.8:6002/s4-ssd1 65
swift-ring-builder account-2.builder add r1z2-1.1.5.8:6002/s4-ssd2 65
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata1-p3 16
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata2 20
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata3 20
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata4 20
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata5 20
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata6 20
swift-ring-builder account-2.builder add r2z1-1.3.2.1:6002/bs1-sata7 20
swift-ring-builder account-2.builder add r2z2-1.3.2.2:6002/bs2-sata1-p3 32
swift-ring-builder account-2.builder add r2z2-1.3.2.2:6002/bs2-sata2-p3 32
swift-ring-builder account-2.builder rebalance

Reassigned 512 (100.00%) partitions. Balance is now 1.07.  Dispersion is now 64.06
-------------------------------------------------------------------------------
NOTE: Dispersion of 64.062500 indicates some parts are not
      optimally dispersed.

      You may want to adjust some device weights, increase
      the overload or review the dispersion report.
-------------------------------------------------------------------------------

How can i reduce the dispersion percentage for this ring, considering i have two zones and four replicas. I also try change weights of devices, but the dispersion stills over 60%.

Any suggestions are welcome?

Regards, Carlos Rodrigues