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Nutanix Cluster Expansion Fails with test_cassandra_ssd_size_check Error

  • Nov 8, 2026 1:59 PM UTC
  • 1 reply
  • 11 views

 

Hello Nutanix Community,

I'm trying to expand an existing 3-node Nutanix cluster by adding a fourth node, but the expansion process fails during the pre-expansion checks with the following error:

Failure in pre expand-cluster tests.
Errors:
Precheck: test_cassandra_ssd_size_check failed.

SSD tier on nodes ['172.22.129.4'] is not sized to accommodate expected metadata growth on cluster.

Refer KB-8842 for more details.

Environment Details:

  • Platform: Cisco UCS C240 M7

  • AOS Version: 7.0

  • Storage Type: Hybrid

  • Existing Cluster: 3 Nodes

  • New Node: 1 Node (4th node)

Additional Information:

  • The new node has the same SSD and HDD configuration as the existing nodes.

  • The SSD capacity on the affected node (172.22.129.4) is identical to the other cluster nodes.

  • The issue occurs during the pre-expansion validation stage.

My Questions:

  1. What could cause this error if all nodes have identical SSD configurations and capacities?

  2. What troubleshooting steps would you recommend to identify the root cause?

  3. Has anyone encountered and successfully resolved this issue during cluster expansion?

Any suggestions or guidance would be highly appreciated.

Thanks in advance!

1 reply

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Hi,
If this is production open a case with Nutanix support team and they will provide you with the required support.
I also like to know how you got the 4th node, was it calculated by a nutanix presales engineer?
what do you see when you run below command from one of CVMs:
nodetool -h 0 ring
the affected node is one of your existing nodes ?
as per the same kb which you have shared, it is mentioned “For new deployments starting from AOS 6.7 and later it is recommended that the size of the SSD Tier is at least 4% or 10% of the total storage capacity of the node based on RPO and node capacity configure”which could be relevant to your case

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