Use SAP and VMware sizing guidelines to size CPU and memory for the SAP HANA VMs. SAP does not allow overcommitment of CPU and memory resources. An SAP HANA scale-up VM can use either 0.5 (half-socket), one, two, three, or four sockets. Odd multiples of half-socket VMs are not allowed—for example, 1.5-socket or 2.5-socket VMs.
An SAP HANA scale-up VM requires a minimum of eight physical cores and supports up to 256 vCPUs, that is, logical cores with Intel Hyper-Threading Technology enabled.
Note: An SAP HANA scale-out VM must be a four-socket wide VM (P580N) that uses all available CPU resources.
You can use the VM configuration parameter numa.nodeAffinity to assign an SAP HANA VM to a specific CPU socket. For example, if a VM using two sockets and 20 cores per socket must run on CPU 0 and 1, set the parameters for the VM as shown in the following figure:
Figure 1. VM CPU settings
To set the numa.nodeAffinity parameter, select Edit settings > VM Options > Advanced > Edit Configuration > Add Configuration Params. The Configuration Parameters window is displayed, as shown in the following figure:
Figure 2. VM configuration parameter numa.nodeAffinity
Note: This section is relevant only for solutions that use Intel Optane PMem on the VxRail nodes.
Add the NVDIMMs as new NVDIMM devices on the SAP HANA VM, as shown in the following figure:
Figure 3. Adding NVDIMM devices to the VM
After powering on the VM, verify that the operating system has correctly detected the NVDIMM device by running the ndctl list command.
The use of Intel Optane PMem in App Direct mode creates additional NUMA nodes. To configure an Intel Optane PMem-enabled VM for optimal performance, you must align the VM configuration to the underlying server hardware and to the NUMA configuration in particular.
NVDIMMs are the VMware representation of Optane PMem. For information about how to configure the NVDIMMs and align them to the NUMA architecture of the physical server, see the VMware Knowledge Base article 78094: .
By default, the Optane PMem allocation in Vmkernel for VM NVDIMMs does not take NUMA into consideration. As a result, the VM might be running on a certain NUMA node while the Optane PMem is allocated from a different NUMA node, causing NVDIMM access in the VM to be remote and leading to poor performance. Resolve this issue by using vCenter to add the settings shown in the following example to a VM configuration. Select Edit VM settings > VM Options > Advanced > Edit Configuration Parameters > Add Parameter for each of the key value pairs shown.
On a four-socket wide VM with four NVDIMMs:
where sched.pmem.prealloc pre-allocates the entire NVDIMM as part of VM startup, preventing a runtime allocation overhead when the VM uses an NVDIMM page for the first time. The setting improves initial writes to Optane PMem but increases the boot time of the VM.
Make SAP HANA aware of the new Intel Optane memory DIMMs.
In the [persistence] section of the global.ini file, provide a comma-separated list of all mounted PMem devices by running:
basepath_persistent_memory_volumes=/hana/pmem/0;/hana/pmem/1; /hana/pmem/2;/hana /pmem/3
The hdblcm tool determines and uses all PMem devices below the /hana/pmem subfolder.