@tvvu The feature of having 40 GB memory target in the ‘Configure CVM’ list is added in AOS 5.20.x version - that’s why you are unable to see it in AOS 5.15 cluster.
Hence, if you are not planning to upgrade AOS to 5.20 version, then for 5.15.x clusters, to increase the CVM memory to 40 GB, you will have to follow a manual process wherein you will have to shut down cvm, change the CVM config file and then start the cvm back up. Once the data resiliency is OK, proceed with the next one.
If the hypervisor is ESXi, then you can refer to KB-2921 for manual steps to change each CVM memory to 40 GB (one at a time)
If the hypervisor is AHV, then kindly reach out to Nutanix Support to perform this change.
