# How much is too much? - Guidelines on storage space utilisation

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We all have a safe number in our head when it comes to storage utilization rate. Depending on professional background the answer will vary between 75%-85%. Sure, would that be of total space? Total space per node? Let’s take a look.

This example assumes a five-node cluster consisting of the following.

• One (1) four-node Model NX-3050

• The physical storage capacity available is 4.48 TBs per node, or 17.92 TBs total
• One (1) node of a Model NX-6060

• The physical storage capacity is 13.91 TBs per node

The total physical storage capacity available to use on this cluster is: (4 x 4.48) + 13.91 = 31.83 TB

• T = 31.83
• N1 = 13.91
• N2 = 4.48

The recommended maximum utilization of this cluster when using Replication Factor of 2

• M = 0.9 x (T - N1 )
• 0.9 x ( 31.83 - 13.91) = 16.128 TB

The recommended maximum utilization of this cluster when using Replication Factor of 3

• M = 0.9 x (T - [N1 + N2])
• 0.9 x (31.83 - [13.91 + 4.48]) = 12.09 TB

Note: The values for storage used in the example are not representative of actual storage available for a Node Model NX-3050.

For calculations formula and more details please see KB-1557 Recommended guidelines for maximum storage utilization on a cluster

For more information on storage management with Nutanix try Prism Web Console Guide: Storage Management