Cisco Hyperflex Sizing Tool



If you know how to size your Cisco Hyperflex system, it’s not that hard! What is the formula ?

(((Disksize in TiB * #Disk per Node * (#Nodes -1)) / VRF) * 0.8 * Dedup * Compression

WOW ! Let’s explain a little bit :

Disksizes are in TB, but the OS see it in TiB. Let’s convert the TB to TiB, so you know how much free space you got in the OS. Right now the disksize is 1.2TB

(#Nodes -1) : This is because when there is a node failure, the data is still everywhere and the system can heal itself.

The VRF is a factor of howmany times a block is written to Hyperflex. VRF is 2 for test-dev or lab environments. The value is 3 for production environments.

0.8 = 20% space saving for NotEnoughSpace

The 20% was a value of the beginning of Hyperflex. It’s no 8% space savings for NotEnoughSpace.


Dedup and compression ration can be set to 1 if you don’t calculate with it.

For a HX220 there is a fixed HDD configuration of 6 HDD’s.

 Number of HX220 Nodes  Capacity in TiB
4 5.24 TiB
5 6.98 TiB
6 8.73 TiB
7 10.43 Tib
8 12.22 TiB


With the HX240 we can add nodes or we can start with nodes with only 6 HDD’s and expand until 23 HDD’s. As long as each node has the same configuration.

HX240 overview.

Number of nodes #HDD per node #HDD per node #HDD per node #HDD per node #HDD per node
 6  11  15  19  23
 4  5.24 TiB  9.6 TiB  12.1 TiB 16.59 TiB 20.08 TiB
 5  6.98 TiB  12.81 TiB  17.46 TiB  22.12 TiB  26.78 TiB
 6  8.73 TiB  16.01 TiB  21.83 TiB 27.65 TiB 33.47 TiB
 7  10.43 TiB  19.21 TiB 26.19 TiB 33.18 TiB 40.16 TiB
 8  12.22 TiB  22.41 TiB 30.56 TiB 38.71 TiB 46.86 TiB

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